Antibodies that bind and block triggering receptor expressed on myeloid cells-1 (TREM-1)

ABSTRACT

The invention relates to antibodies that are capable of specifically binding TREM-1 and preventing the activation of TREM-1, a protein expressed on monocytes, macrophages and neutrophils. Such antibodies find utility in the treatment of individuals with an inflammatory disease, such as rheumatoid arthritis and inflammatory bowel disease.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 13/954,318, filed Jul. 30, 2013, currently allowed, which is a continuation-in-part of U.S. application Ser. No. 13/690,748, filed Nov. 30, 2012, granted as U.S. Pat. No. 9,000,127, which claimed priority of European Patent Application 12176892.3, filed Jul. 18, 2012, European Patent Application 12158974.1, filed Mar. 12, 2012, and European Patent Application 12155641.9, filed Feb. 15, 2012; this application also claims priority under 35 U.S.C. § 119(e) of U.S. Provisional Application 61/674,434, filed Jul. 23, 2012, U.S. Provisional Application 61/672,799, filed Jul. 18, 2012, U.S. Provisional Application 61/599,447, filed Feb. 16, 2012, and U.S. Provisional Application 61/598,968, filed Feb. 15, 2012; the contents of all above-named applications are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method of identifying a functional TREM-1 antibody. The invention also relates to antibodies that are capable of specifically binding TREM-1 and which are capable of reducing or blocking TREM-1 activity (signalling and/or activation). Furthermore, the invention relates to uses for such antibodies, such as therapeutic and pharmaceutical uses.

BACKGROUND OF THE INVENTION

Triggering receptor expressed on myeloid cells-1 (TREM-1) is a receptor that is expressed on monocytes, macrophages and neutrophils. When activated, TREM-1 associates with a signalling protein, DAP12, and triggers the release of pro-inflammatory cytokines from the cells that express it (Bouchon et al, J. Immunol. 2000; 164(10): 4991-4995). TREM-1 mRNA and protein expression is known to be upregulated in the myeloid cells of individuals with sepsis, rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). Increasing scientific evidence supports the theory that TREM-1 contributes to the development and progression of inflammatory diseases, as TREM-1 positive monocytes and neutrophils that are recruited to an inflamed area exacerbate inflammation (Bouchon et al. Nature 2001; 410: 1103-1107; Schenk et al, Clin Invest. 2007; 117(10): 3097-3106); Kuai et al., Rheumatology (Oxford). 2009; 48(11):1352-1358.

Antibodies that are capable of binding TREM-1 are known, including the commercially available TREM26 and TREM37 (cat. nos. 314902 and 316102, respectively, Biolegend, San Diego, Calif. 92121, USA), MAB1278 (cat. no. MAB1278, R&D Systems, Minneapolis, Minn. 55413, USA), mAb 6B1 (cat. no. HM2252, Hycult Biotech, Uden, Netherlands) and anti-TREM-1 2E2 (cat. no. HPA005563, Sigma-Aldrich, Denmark). All known TREM-1 antibodies are agonistic when immobilised; that is, they increase cytokine release from monocytes, macrophages and neutrophils. Another characteristic of the known TREM-1 antibodies is that they do not cross-react with TREM-1 from primates, such as cynomolgus monkeys or rhesus monkeys, which means that the known antibodies cannot be tested in these animals.

Thus, there is a need in the art for an antibody that is capable of binding and blocking the function of TREM-1. There is a need in the art for a TREM-1 antibody that is capable of preventing TREM-1 from forming dimers/multimers. There is a need in the art for a TREM-1 antibody that is capable of blocking TREM-1 activation and signalling. There is a need in the art for a TREM-1 antibody that is capable of interfering with the interaction between TREM-1 and its ligand. There is a need in the art for a TREM-1 antibody that is capable of blocking cytokine release from a myeloid cell. There is a need in the art for a TREM-1 antibody that has little or no agonistic activity when soluble or immobilised. There is also a need in the art for an antibody that is capable of binding both human TREM-1 and TREM-1 from one or more other species, such as a primate, in order to enable toxicology investigation as well as assess the pharmacokinetics and pharmacodynamics of the antibody in suitable animal models.

Disclosed herein are TREM-1 antibodies that are suitable for use as pharmaceuticals. Such antibodies may have a substantial impact upon the quality of life of individuals with sepsis or a chronic inflammatory disease such as rheumatoid arthritis, psoriatic arthritis and inflammatory bowel disease.

SUMMARY

The present invention relates to a method of identifying a functional TREM-1 antibody, comprising (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell when said cell is incubated with a TREM-1 modifying agent; (c) contacting the co-culture of (b) with a TREM-1 antibody; and (d) measuring that the activity of the first cell is less than or more than the activity measured in (b).

The method may be tailored to identify a blocking TREM-1 molecule, such as an antibody. The method of identifying a blocking TREM-1 antibody comprises (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell when said cell is incubated with an activating compound, such as a TREM-1 ligand, or an activated neutrophil; (c) contacting the co-culture of the first cell and the activating compound, such as a TREM-1 ligand, or an activated neutrophil with a TREM-1 antibody; and (d) measuring that the activity of the first cell is less than the activity measured in (b).

The method may be tailored to identify a stimulating TREM-1 antibody. The method of identifying a stimulating TREM-1 antibody comprises (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell; (c) contacting/incubating said cell with a TREM-1 antibody; and (d) measuring that the activity of the first cell is more than the activity of the measured in (b).

The first cell may be of haematopoetic origin. The modifying agent of (b) may be an activated neutrophil or a TREM-1 ligand. The signalling protein may be DAP10, DAP12, TCR zeta, Fc gamma RIII and an Fc receptor, or a portion thereof. The signalling protein may signal via a transcription factor such as NFAT or NFκB. The reporter gene may be a gene that is not natively expressed in said first cell and may be a gene that encodes β-galactosidase, luciferase, green flourescent protein (GFP) or chloramphenicol transferase. The present invention also relates to stimulating TREM-1 antibodies that may be identified by means of the invented method.

The present invention relates to antibodies that are capable of specifically binding to TREM-1 and that are capable of blocking TREM-1 function. Said antibodies may be capable of preventing or reducing the dimerisation or multimerisation of TREM-1. Said antibodies may be capable of blocking the interaction between TREM-1 and its ligand, or the antibodies may be capable of blocking the TREM-1 function that is induced by a TREM-1 ligand. The TREM-1 may be human TREM-1 and/or TREM-1 from another species than a human, such as TREM-1 from another primate than a human.

Antibodies of the invention may be capable of competing with mAb 0170 for binding to human TREM-1. Antibodies of the invention may be capable of specifically binding a polypeptide comprising amino acids D38 to F48 of SEQ ID NO: 1 (human TREM-1). Antibodies of the invention may have an epitope comprising one, two, three, four, five, six, seven or all of the amino acid residues selected from the group consisting of the D38, V39, K40, C41, D42, Y43, T44 and L45 of SEQ ID NO: 1 (human TREM-1) and one, two or all of the amino acid residues selected from the group consisting of the E46, K47 and F48 of SEQ ID NO: 1 (human TREM-1), as may be determined using HX-MS. Antibodies of the invention may have an epitope comprising one, two, three or all of the amino acid residues selected from the group consisting of the D42, E46, D92 and H93 of SEQ ID NO: 1 (human TREM-1), as may be determined by measuring antibody binding to variants of TREM-1.

Antibodies of the invention may be capable of competing with mAb 0170 for binding to cynomolgus monkey TREM-1. Antibodies of the invention may be capable of capable of specifically binding a polypeptide comprising amino acids E19 to L26 of cynomolgus monkey TREM-1 (SEQ ID NO: 12), or the corresponding amino acids of SEQ ID NO: 21, as may be determined using HX-MS.

Antibodies of the invention may be used as pharmaceuticals for the treatment of individuals with one or more autoimmune diseases and/or chronic inflammation. Hence, the present invention also relates to a method of treatment of individuals with one or more autoimmune diseases and/or chronic inflammation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Activation of the BWZ.36/hTREM-1:DAP12:NFAT-LacZ cell line (herein also referred to as the “BWZ/hTREM-1 reporter cell”) is reduced by antibodies such as 14F128 and 14F113 but not by the commercially available antibodies MAB1278 MAB1278 (R&D Systems, Minneapolis, Minn. 55413, USA: Cat. No. MAB1278), anti-TREM-1 HPA (Sigma, USA: Cat. No. HPA005563), aTREM26 (Biolegend, San Diego, Calif. 92121, USA: Cat. No. 314902) and aTREM37 (Biolegend, San Diego, Calif. 92121, USA: Cat. No. 316102).

FIG. 2: The BWZ/hTREM-1 reporter cell alone or co-cultured with TLRL pre-stimulated neutrophils. TLRL activated neutrophils are able to induce a 15-fold increase in the signal (luminescence), compared to non-activated neutrophils (see the last two columns). The positive control (the platebound, agonistic MAB1278 (R&D Systems, Minneapolis, Minn. 55413, USA: Cat. no. MAB1278) gave a 32-fold induction in this experiment (see second column). Data are plotted as means±SEM (n=3).

FIG. 3: A normalised reporter assay, in which TREM-1 is stimulated by PGN-activated neutrophils, shows that the commercially available antibodies TREM-26 (cat. no. 314902, Biolegend, San Diego, Calif. 92121, USA), TREM-37 (cat. no. 316102, Biolegend, San Diego, Calif. 92121, USA), MAB1278 (cat. no. MAB1278, R&D Systems, Minneapolis, Minn. 55413, USA), and anti-TREM-1 HPA (cat. no. HPA005563, Sigma, St Louis, Mo., USA) are agonistic antibodies that enhance the TREM-1 dependent luminescence signal in the reporter assay (giving a signal higher than 1). The antibody identified as 5F27A1 and 14F69 are shown to be the best blocker (giving a signal less than 0.5). Data plotted as mean±SEM (n=3). Isotype control MABOO2 (cat. no. MAB002, R&D Systems, Minneapolis, Minn. 55413, USA). All antibodies have been used at 1 μg/ml.

FIG. 4: Activity in the BWZ/hTREM-1 reporter assay. On the x-axis, TREM-1 blocking activity is shown as the activity that remained when 0.2 μg/ml antibody was added to the BWZ/hTREM-1 reporter cell, which had been pre-activated with PGN-stimulated neutrophils. When TREM-1 antibodies were platebound, some (including all of the commercially available TREM-1 antibodies) were able to crossbind TREM-1 and thereby activate TREM-1. This activity is shown on the y-axis. Thus, the antibodies shown as dots in the box in the lower left-hand corner all show different properties compared to known antibodies, being advantageously blocking and not agonistic.

FIG. 5: Binding of human TREM-1 antibodies to PBMCs from a rhesus monkey. In the upper left corner, it is shown that most of the antibodies only bound human TREM-1 (each black dot represents one antibody). Some antibodies, such as mAbs 0025 and 14F128, 14F11, 14F29, 14F113 and 14F69, were able to bind to both human TREM-1 and rhesus monkey TREM-1, showing cross-reactivity.

FIG. 6A-6C: Binding of anti-human TREM-1 antibodies to PBMCs from a cynomolgus monkey. FIG. 6A: In the upper left corner, it is shown that most antibodies only bound human TREM-1 (each black dot represents one antibody). Some antibodies, such as mAb 0025 and 14F128, 14F11, 14F29, were able to bind both human and cynomolgus monkey TREM-1, showing cross-reactivity. Some antibodies, such as 14F69 (mAb 0044), are able to bind cynomolgus monkey PBMCs (FIG. 6B) and human PBMCs (FIG. 6C) equally well.

FIG. 7A-7D: Sequence coverage of HX analyzed peptides of hTREM-1 (residues 21-200 of SEQ ID NO: 1) in the presence and absence of mAb 0023 or mAb 0026 (FIG. 7A), mAb 0024 or Biolegend Clone 26 (FIG. 7B), mAb 0025 (FIG. 7C) or RnD Biosystems' MAB1278 (FIG. 7D). The primary sequence (residues 21-201 of SEQ ID NO: 1) is displayed above the HX analyzed peptides (shown as horizontal bars). Peptides showing similar exchange patterns both in the presence and absence of mAbs are displayed in white, whereas peptides showing reduced deuterium incorporation upon mAb binding are coloured black. Boxed sequence regions define the epitope.

FIG. 8: Structural mapping of the epitope of mAb 0025 on hTREM-1. The structure of hTREM-1 (pdb 1Q8M) is represented with one part of the dimer as black C-alpha wire. The other part of the hTREM-1 dimer is shown in grey ribbon with the 0025 epitope displayed in black.

FIG. 9: The BWZ/hTREM-1 reporter cell co-cultured with TREM-1 ligand complex reflects the TREM-1 functionality which was dose-dependently inhibited by TREM-1 mAb-0170.

FIG. 10: TNFalpha release from M2 macrophages stimulated by PGLYRP-1 was blocked by TREM-1 antibodies.

FIG. 11: The human TREM-1 (residues 17-200 of SEQ ID NO:1) and cynomolgus monkey TREM-1 (residues 2-180 of SEQ ID NO:12) sequences are aligned. Amino acid residues that differ between the two are shown in bold type. Residues that have been shown to be within the epitope (as determined using HX-MS and surface plasmon resonance) are highlighted.

BRIEF DESCRIPTION OF THE SEQUENCES

SEQ ID NO: 1 represents the amino acid sequence of wild type (wt) human TREM-1.

SEQ ID NO: 2 represents the amino acid sequence of the variable heavy chain of the m14F69 antibody.

SEQ ID NO: 3 represents the amino acid sequence of the variable light chain of the m14F69 antibody.

SEQ ID NO: 4 represents the amino acid sequence of the heavy chain of a first humanised TREM-1 antibody (mAb 0170).

SEQ ID NO: 5 represents the amino acid sequence of the light chain of a first humanised TREM-1 antibody (mAB 0170).

SEQ ID NO: 6 represents the amino acid sequence of the heavy chain of a second humanised TREM-1 antibody (mAb 0122).

SEQ ID NO: 7 represents the amino acid sequence of the light chain of a second humanised TREM-1 antibody (mAb 0122).

SEQ ID NO: 8 represents the amino acid sequence of the heavy chain of the m14F128 antibody.

SEQ ID NO: 9 represents the amino acid sequence of the light chain of the m14F128 antibody.

SEQ ID NO: 10 represents the amino acid sequence of the heavy chain of the m14F113 antibody.

SEQ ID NO: 11 represents the amino acid sequence of the light chain of the m14F113 antibody.

SEQ ID NO: 12 represents the amino acid sequence of the extracellular domain of wild type (wt) cynomolgus monkey (c) TREM-1, when expressed in E. coli.

SEQ ID NO: 13 represents the amino acid sequence of K20A-hTREM-1-Cmyc2-His6 (construct 0222).

SEQ ID NO: 14 represents the amino acid sequence of A24T/Y28F/N30S/R32Q/P70H-cTREM-1-Cmyc2-His6 (construct 0244).

SEQ ID NO: 15 represents the amino acid sequence of A24T/Y28F/N30S/R32Q/E54K-cTREM-1-Cmyc2-His6 (construct 0245).

SEQ ID NO: 16 represents the nucleic acid sequence of a primer.

SEQ ID NO: 17 represents the nucleic acid sequence of a primer.

SEQ ID NO: 18 represents the amino acid sequence of human (h) TREM-1(1-134)-His6.

SEQ ID NO: 19 represents the amino acid sequence of cTREM-1-Cmyc2-His6 (construct 0238).

SEQ ID NO: 20 represents the amino acid sequence of hTREM-1-Cmyc2-His6 (construct 0247).

SEQ ID NO: 21 represents the amino acid sequence of full length cTREM-1.

SEQ ID NO: 22 represents the amino acid sequence of full length murine (m) TREM-1.

SEQ ID NO: 23 represents the amino acid sequence of full length hPGLYRP1.

SEQ ID NO: 24 represents the amino acid sequence of the extracellular IgV-like domain of human TREM-1, Met-human (h) TREM-1 (21-134).

SEQ ID NO: 25 represents the amino acid sequence of the heavy chain of the Fab region of monoclonal antibody (mAb) 0170.

SEQ ID NO: 26 represents the amino acid sequence of the light chain of the Fab region of monoclonal antibody (mAb) 0170.

DESCRIPTION

TREM-1 is a transmembrane protein that consists of 234 amino acids, including a single extracellular immunoglobulin domain and a short cytoplasmic tail with no apparent signaling motif. When activated, TREM-1 associates with the ITAM-containing signaling adaptor protein, DAP12. Downstream signalling may include activation of the NFAT transcription factor, causing an upregulation of pro-inflammatory cytokine production.

The present invention relates to antibodies that are capable of specifically binding and blocking the function of TREM-1. Antibodies of the invention may block TREM-1 function by reducing/blocking TREM-1 activation and downstream signalling.

Antibodies according to the invention may block TREM-1 by means of one of one or a combination of several different mechanisms, blocking TREM-1 directly or indirectly. For example, antibodies of the invention may prevent the natural ligand of TREM-1, peptidoglycan recognition protein 1 (PGLYRP1), from creating a functional complex with TREM-1 and/or antibodies of the invention may block TREM-1 by preventing individual TREM-1 molecules from forming dimers or multimers. TREM-1 dimerisation or multimerisation may be reduced or prevented by TREM-1 antibodies that are capable of binding to a portion of TREM-1 that would otherwise reside in the interface of a TREM-1 dimer, thus preventing individual TREM-1 molecules from associating with one another. TREM-1 dimerisation or multimerisation may be reduced or prevented by TREM-1 antibodies that interfere with the interaction of TREM-1 with its ligand. Antibodies according to the current invention may block PGLYRP1-induced activation of TREM-1. PGLYRP1, a highly conserved, 196 amino acid long protein consisting of a signal peptide and a peptidoglycan binding domain, is expressed in neutrophils and released upon their activation. Antibodies according to the current invention may down-regulate pro-inflammatory cytokine release from myeloid cells. Antibodies according to the current invention may block the release of TNFalpha, MIP-1beta, MCP-1, IL-1beta, GM.CSF, IL-6 and/or IL-8 from macrophages, neutrophils, synovial tissue cells and/or a reporter cell, as disclosed herein.

Antibodies of the invention may be capable of binding both human TREM-1 and TREM-1 from another species than a human being. The term “TREM-1”, as used herein, thus encompasses any naturally occurring form of TREM-1 which may be derived from any suitable organism. For example, TREM-1 for use as described herein may be vertebrate TREM-1, such as mammalian TREM-1, such as TREM-1 from a primate (such as a human, a chimpanzee, a cynomolgus monkey or a rhesus monkey); a rodent (such as a mouse or a rat), a lagomorph (such as a rabbit), or an artiodactyl (such a cow, sheep, pig or camel). Preferably, the TREM-1 is SEQ ID NO: 1 (human TREM-1). The TREM-1 may be a mature form of TREM-1 such as a TREM-1 protein that has undergone post-translational processing within a suitable cell. Such a mature TREM-1 protein may, for example, be glycosylated. The TREM-1 may be a full length TREM-1 protein.

Antibodies of the invention may be monoclonal antibodies, in the sense that they are directly or indirectly derived from a single clone of a B lymphocyte. TREM-1 antibodies may be produced, screened and purified using, for example, the methods described in the Examples. In brief, a suitable mouse such as a TREM-1 or TREM-1/TREM-3 knock-out (KO) mouse may be immunised with TREM-1, a cell expressing TREM-1 or a combination of both.

Antibodies of the invention may be polyclonal in the sense of being a mixture of monoclonal antibodies according to the current invention.

Primary screening of hybridoma supernatants may be performed using direct ELISA or FMAT and secondary screening may be performed using flow cytometry. Positive hybridoma supernatants may then be screened in a reporter gene assay.

Antibodies may be recombinantly expressed in prokaryotic or eukaryotic cells. The prokaryotic cell may be E. coli. The eukaryotic cell may be a yeast, insect or mammalian cell, such as a cell derived from an organism that is a primate (such as a human, a chimpanzee, a cynomolgus monkey or a rhesus monkey), a rodent (such as a mouse or a rat), a lagomorph (such as a rabbit) or an artiodactyl (such a cow, sheep, pig or camel). Suitable mammalian cell lines include, but are not limited to, HEK293 cells, CHO cells and HELA cells. TREM-1 antibodies may also be produced by means of other methods known to the person skilled in the art, such as a phage display or a yeast display.

Once produced, antibodies may be screened for binding to, for example, full length TREM-1 or mutants thereof using the methods described in the Examples.

One embodiment of the current invention is a method of identifying a functional TREM-1 antibody. Antibodies that are capable of specifically binding TREM-1 and that have any effect upon TREM-1 activation and downstream signalling are herein referred to as “functional TREM-1 antibodies”. A “functional” TREM-1 antibody herein refers to an antibody that is capable of blocking or stimulating TREM-1. The method of identifying a functional TREM-1 antibody comprises (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell when said cell is incubated with a TREM-1 modifying agent; (c) contacting the co-culture of (b) with a TREM-1 antibody; and (d) measuring that the activity of the first cell is less than or more than the activity measured in (b).

The “first cell” of (a) may be a cell of haematopoetic origin, such as a myeloid cell, such as a T-cell. The signalling protein of (a) may be any signalling protein that is capable of forming a complex with TREM-1. Suitable signalling proteins include DAP10, DAP12, TCR zeta, Fc gamma RIII and an Fc receptor, or part thereof. The reporter construct of (a) may be any construct that is capable of being activated via the signalling protein and generating a recognisable signal. Suitable reporter constructs comprise a transcription factor and a reporter gene. The signalling protein may signal via a transcription factor selected from the group consisting of the NFAT and NFkB. The reporter gene is a gene that is not natively expressed in said first cell and may be a gene that encodes β-galactosidase, luciferase, green flourescent protein (GFP) or chloramphenicol transferase. Said first cell may be transfected with a transcription factor and a reporter gene using methods that are well known in the art.

The “BWZ/hTREM-1 reporter cell” described in the Examples is one example of a “first cell”.

The modifying agent of (b) may be a TREM-1 ligand or an activated neutrophil. The “TREM-1 antibody” of (c) may be a TREM-1 specific hybridoma supernatant or a purified antibody. The activity measured in (d) is the signal produced by the reporter construct. An example of such signalling is the luminescence caused by NFAT-driven LacZ (R-lactamase luciferase) production.

The method may be tailored to identify a blocking TREM-1 antibody. The method of identifying a blocking TREM-1 antibody comprises (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell when said cell is incubated with an activated neutrophil; (c) contacting the co-culture of the first cell and the activated neutrophil with a TREM-1 antibody; and (d) measuring that the activity of the first cell is less than the activity measured in (b).

The method may also be tailored to identify a stimulating TREM-1 antibody. The method of identifying a stimulating TREM-1 antibody comprises (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell; (c) contacting/incubating said cell with a TREM-1 antibody; and (d) measuring that the activity of the first cell is more than the activity of the measured in (b).

The present invention relates to blocking TREM-1 antibodies that may be identified by means of the method, herein disclosed, of identifying a blocking antibody. When tested using the method described above and in the Examples, an antibody according to the current invention may, at a concentration of less than 100 μg/ml—such as less than 90 μg/ml, such as less than 80 μg/ml, such as less than 70 μg/ml, such as less than 60 μg/ml, such as less than 50 μg/ml, such as less than 40 μg/ml, such as less than 30 μg/ml, such as less than 20 μg/ml, such as less than 10 μg/ml, such as less than 5 μg/ml, such as less than 1 μg/ml—be capable of reducing the activity of said first cell by 50%, such as 60%, such as 70%, such as 80%, such as 90%, such as 95%, such as 100%. An antibody according to the invention may be capable of completely extinguishing the activity of the first cell. When tested using the method described above and in the Examples, an antibody according to the current invention may, at a concentration of less than 1 μg/ml—such as less than 0.9 μg/ml, such as less than 0.8 μg/ml, such as less than 0.7 μg/ml, such as less than 0.6 μg/ml, such as less than 0.5 μg/ml, such as less than 0.4 μg/ml, such as less than 0.3 μg/ml, such as less than 0.2 μg/ml—be capable of extinguishing the activity of the first cell.

The present invention also relates to blocking TREM-1 antibodies that may be identified by other means than the method herein disclosed.

The term “antibody” herein refers to a protein, derived from a germline immunoglobulin sequence, which is capable of specifically binding to an antigen (TREM-1) or a portion thereof. The term includes full length antibodies of any class or isotype (that is, IgA, IgE, IgG, IgM and/or IgY) and any single chain or fragment thereof. An antibody that specifically binds to an antigen, or portion thereof, may bind exclusively to that antigen, or portion thereof, or it may bind to a limited number of homologous antigens, or portions thereof. Full-length antibodies usually comprise at least four polypeptide chains: two heavy (H) chains and two light (L) chains that are interconnected by disulfide bonds. One immunoglobulin sub-class of particular pharmaceutical interest is the IgG family. In humans, the IgG class may be sub-divided into 4 sub-classes: IgG1, IgG2, IgG3 and IgG4, based on the sequence of their heavy chain constant regions. The light chains can be divided into two types, kappa and lambda, based on differences in their sequence composition. IgG molecules are composed of two heavy chains, interlinked by two or more disulfide bonds, and two light chains, each attached to a heavy chain by a disulfide bond. A heavy chain may comprise a heavy chain variable region (VH) and up to three heavy chain constant (CH) regions: CH1, CH2 and CH3. A light chain may comprise a light chain variable region (VL) and a light chain constant region (CL). VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDRs), interspersed with regions that are more conserved, termed framework regions (FR). VH and VL regions are typically composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The hypervariable regions of the heavy and light chains form a [binding] domain that is capable of interacting with an antigen, whilst the constant region of an antibody may mediate binding of the immunoglobulin to host tissues or factors, including but not limited to various cells of the immune system (effector cells), Fc receptors and the first component (Clq) of the classical complement system.

Antibodies of the current invention may be isolated. The term “isolated antibody” refers to an antibody that has been separated and/or recovered from (an)other component(s) in the environment in which it was produced and/or that has been purified from a mixture of components present in the environment in which it was produced.

Certain antigen-binding fragments of antibodies may be suitable in the context of the current invention, as it has been shown that the antigen-binding function of an antibody can be performed by fragments of a full-length antibody. The term “antigen-binding fragment” of an antibody refers to one or more fragment(s) of an antibody that retain the ability to specifically bind to an antigen, such as TREM-1, as described herein. Examples of antigen-binding fragments include Fab, Fab′, F(ab)2, F(ab′)2, F(ab)S, Fv (typically the VL and VH domains of a single arm of an antibody), single-chain Fv (scFv; see e.g., Bird et al., Science 1988; 242:42S-426; and Huston et al. PNAS 1988; 85:5879-5883), dsFv, Fd (typically the VH and CHI domain), and dAb (typically a VH domain) fragments; VH, VL, VhH, and V-NAR domains; monovalent molecules comprising a single VH and a single VL chain; minibodies, diabodies, triabodies, tetrabodies, and kappa bodies (see, e.g., Ill et al., Protein Eng 1997; 10:949-57); camel IgG; IgNAR; as well as one or more isolated CDRs or a functional paratope, where the isolated CDRs or antigen-binding residues or polypeptides can be associated or linked together so as to form a functional antibody fragment. Various types of antibody fragments have been described or reviewed in, e.g., Holliger and Hudson, Nat Biotechnol 2005; 2S:1126-1136; WO2005040219, and published U.S. Patent Applications 20050238646 and 20020161201. These antibody fragments may be obtained using conventional techniques known to those of skill in the art, and the fragments may be screened for utility in the same manner as intact antibodies.

An antibody of the invention may be a human antibody or a humanised antibody. The term “human antibody”, as used herein, is intended to include antibodies having variable regions in which at least a portion of a framework region and/or at least a portion of a CDR region are derived from human germline immunoglobulin sequences. (For example, a human antibody may have variable regions in which both the framework and CDR regions are derived from human germline immunoglobulin sequences.) Furthermore, if the antibody contains a constant region, the constant region is also derived from human germline immunoglobulin sequences. The human antibodies of the invention may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo).

Such a human antibody may be a human monoclonal antibody. Such a human monoclonal antibody may be produced by a hybridoma which includes a B cell obtained from a transgenic nonhuman animal, e.g., a transgenic mouse, having a genome comprising a human heavy chain transgene and a light chain transgene fused to an immortalized cell.

Human antibodies may be isolated from sequence libraries built on selections of human germline sequences, further diversified with natural and synthetic sequence diversity.

Human antibodies may be prepared by in vitro immunisation of human lymphocytes followed by transformation of the lymphocytes with Epstein-Barr virus.

The term “human antibody derivative” refers to any modified form of the human antibody, such as a conjugate of the antibody and another agent or antibody.

The term “humanised antibody”, as used herein, refers to a human/non-human chimeric antibody that contains one or more sequences (CDR regions or parts thereof) that are derived from a non-human immunoglobulin. A humanised antibody is, thus, a human immunoglobulin (recipient antibody) in which at least residues from a hyper-variable region of the recipient are replaced by residues from a hyper-variable region of an antibody from a non-human species (donor antibody) such as from a mouse, rat, rabbit or non-human primate, which have the desired specificity, affinity, sequence composition and functionality. In some instances, FR residues of the human immunoglobulin are replaced by corresponding non-human residues. An example of such a modification is the introduction of one or more so-called back-mutations, which are typically amino acid residues derived from the donor antibody. Humanisation of an antibody may be carried out using recombinant techniques known to the person skilled in the art (see, e.g., Antibody Engineering, Methods in Molecular Biology, vol. 248, edited by Benny K. C. Lo). A suitable human recipient framework for both the light and heavy chain variable domain may be identified by, for example, sequence or structural homology. Alternatively, fixed recipient frameworks may be used, e.g., based on knowledge of structure, biophysical and biochemical properties. The recipient frameworks can be germline derived or derived from a mature antibody sequence. CDR regions from the donor antibody can be transferred by CDR grafting. The CDR grafted humanised antibody can be further optimised for e.g. affinity, functionality and biophysical properties by identification of critical framework positions where re-introdution (backmutation) of the amino acid residue from the donor antibody has beneficial impact on the properties of the humanised antibody. In addition to donor antibody derived backmutations, the humanised antibody can be engineered by introduction of germline residues in the CDR or framework regions, elimination of immunogenic epitopes, site-directed mutagenesis, affinity maturation, etc.

Furthermore, humanised antibodies may comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance. In general, a humanised antibody will comprise at least one—typically two—variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin and in which all or substantially all of the FR residues are those of a human immunoglobulin sequence. The humanised antibody can, optionally, also comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin.

The term “humanised antibody derivative” refers to any modified form of the humanised antibody, such as a conjugate of the antibody and another agent or antibody.

The term “chimeric antibody”, as used herein, refers to an antibody whose light and heavy chain genes have been constructed, typically by genetic engineering, from immunoglobulin variable and constant region genes that originate from different species. For example, the variable segments of genes from a mouse monoclonal antibody may be joined to human constant segments.

The fragment crystallisable region (“Fc region”/“Fc domain”) of an antibody is the N-terminal region of an antibody, which comprises the constant CH2 and CH3 domains. The Fc domain may interact with cell surface receptors called Fc receptors, as well as some proteins of the complement system. The Fc region enables antibodies to interact with the immune system. In one aspect of the invention, antibodies may be engineered to include modifications within the Fc region, typically to alter one or more of its functional properties, such as serum half-life, complement fixation, Fc-receptor binding, protein stability and/or antigen-dependent cellular cytotoxicity, or lack thereof, among others. Furthermore, an antibody of the invention may be chemically modified (e.g., one or more chemical moieties can be attached to the antibody) or be modified to alter its glycosylation, again to alter one or more functional properties of the antibody. An IgG1 antibody may carry a modified Fc domain comprises one or more, and perhaps all of the following mutations that will result in decreased affinity to certain Fc receptors (L234A, L235E, and G237A) and in reduced C1q-mediated complement fixation (A330S and P331S), respectively (residue numbering according to the EU index).

The isotype of an antibody of the invention may be IgG, such as IgG1, such as IgG2, such as IgG4. If desired, the class of an antibody may be “switched” by known techniques. For example, an antibody that was originally produced as an IgM molecule may be class switched to an IgG antibody. Class switching techniques also may be used to convert one IgG subclass to another, for example: from IgG1 to IgG2 or IgG4; from IgG2 to IgG1 or IgG4; or from IgG4 to IgG1 or IgG2. Engineering of antibodies to generate constant region chimeric molecules, by combination of regions from different IgG subclasses, can also be performed.

In one embodiment, the hinge region of CH1 is modified such that the number of cysteine residues in the hinge region is altered, e.g., increased or decreased. This approach is described further for instance in U.S. Pat. No. 5,677,425 by Bodmer et al.

The constant region may be modified to stabilize the antibody, e.g., to reduce the risk of a bivalent antibody separating into two monovalent VH-VL fragments. For example, in an IgG4 constant region, residue S228 (residue numbering according to the EU index) may be mutated to a proline (P) residue to stabilise inter heavy chain disulphide bridge formation at the hinge (see, e.g., Angal et al., Mol Immunol. 1995; 30: 105-8).

Antibodies or fragments thereof may also be defined in terms of their complementarity-determining regions (CDRs). The term “complementarity-determining region” or “hypervariable region”, when used herein, refers to the regions of an antibody in which amino acid residues involved in antigen binding are situated. The region of hypervariability or CDRs can be identified as the regions with the highest variability in amino acid alignments of antibody variable domains. Databases can be used for CDR identification such as the Kabat database, the CDRs e.g. being defined as comprising amino acid residues 24-34 (L1), 50-56 (L2) and 89-97 (L3) of the light-chain variable domain and 31-35 (H1), 50-65 (H2) and 95-102 (H3) in the heavy-chain variable domain; (Kabat et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242) Alternatively CDRs can be defined as those residues from a “hypervariable loop” (residues 26-33 (L1), 50-52 (L2) and 91-96 (L3) in the light-chain variable domain and 26-32 (H1), 53-55 (H2) and 96-101 (H3) in the heavy-chain variable domain; Chothia and Lesk, J. Mol. Biol 1987; 196: 901-917). Typically, the numbering of amino acid residues in this region is performed by the method described in Kabat et al., supra. Phrases such as “Kabat position”, “Kabat residue”, and “according to Kabat” herein refer to this numbering system for heavy chain variable domains or light chain variable domains. Using the Kabat numbering system, the actual linear amino acid sequence of a peptide may contain fewer or additional amino acids corresponding to a shortening of, or insertion into, a framework (FR) or CDR of the variable domain. For example, a heavy chain variable domain may include amino acid insertions (residue 52a, 52b and 52c according to Kabat) after residue 52 of CDR H2 and inserted residues (e.g. residues 82a, 82b, and 82c, etc. according to Kabat) after heavy chain FR residue 82. The Kabat numbering of residues may be determined for a given antibody by alignment at regions of homology of the sequence of the antibody with a “standard” Kabat numbered sequence.

The term “framework region” or “FR” residues refer to those VH or VL amino acid residues that are not within the CDRs, as defined herein.

The m14F69 antibody has a variable heavy chain sequence as shown in SEQ ID NO: 2 and a variable light chain sequence as shown in SEQ ID NO: 3. An antibody of the invention may comprise this variable heavy chain sequence and/or this variable light chain sequence. The m14F69 antibody has the CDR sequences shown at amino acids 31 to 35, 50 to 68 and 101 to 110 of SEQ ID NO: 2 and amino acids 24 to 38, 54 to 60 and 93 to 101 of SEQ ID NO: 3. An antibody of the invention may comprise 1, 2, 3, 4, 5 or all 6 of these CDR sequences. An antibody of the invention may comprise amino acids 101 to 110 of SEQ ID NO: 2.

The heavy chain of an antibody according to the invention may comprise a CDR1 sequence of amino acids 31 to 35 (TYAMH) of SEQ ID NO: 2, wherein one of these amino acids may be substituted by a different amino acid.

The heavy chain of an antibody according to the invention may comprise a CDR2 sequence of amino acids 50 to 68 (RIRTKSSNYATYYADSVKD) of SEQ ID NO: 2, wherein one, two or three of these amino acids may be substituted by a different amino acid.

The heavy chain of an antibody according to the invention may comprise a CDR3 sequence of amino acids 101 to 110 (DMGQRRQFAY) of SEQ ID NO: 2, wherein one, two or three of these amino acids may be substituted by a different amino acid.

The light chain of an antibody according to the invention may comprise a CDR1 sequence of amino acids 24 to 38 (RASESVDTFDYSFLH) of SEQ ID NO: 3, wherein one, two or three of these amino acids may be substituted with a different amino acid.

The light chain of an antibody according to the invention may comprise a CDR2 sequence of amino acids 54 to 60 (RASNLES) of SEQ ID NO: 3, wherein one or two of these amino acids may be substituted with a different amino acid.

The light chain of an antibody according to the invention may comprise a CDR3 sequence of amino acids 93 to 101 (QQSNEDPYT) of SEQ ID NO: 3, wherein one or two of these amino acids may be substituted with a different amino acid.

The mAb 0170 antibody has a heavy chain sequence as shown in SEQ ID NO: 4 and a light chain sequence as shown in SEQ ID NO: 5. An antibody of the invention may comprise this heavy chain sequence and/or this light chain sequence. The mAb 0170 antibody has the CDR sequences shown at amino acids 31 to 35, 50 to 68 and 101 to 110 of SEQ ID NO: 4 and amino acids 24 to 38, 54 to 60 and 93 to 101 of SEQ ID NO: 5. An antibody of the invention may comprise 1, 2, 3, 4, 5 or all 6 of these CDR sequences.

The mAb 0122 antibody has a heavy chain sequence as shown in SEQ ID NO: 6 and a light chain sequence as shown in SEQ ID NO: 7. An antibody of the invention may comprise this heavy chain sequence and/or this light chain sequence. The mAb 0122 antibody has the CDR sequences shown at amino acids 31 to 35, 50 to 68 and 101 to 110 of SEQ ID NO: 6 and amino acids 24 to 38, 54 to 60 and 93 to 101 of SEQ ID NO: 7. An antibody of the invention may comprise 1, 2, 3, 4, 5 or all 6 of these CDR sequences.

The heavy chain of an antibody according to the invention may comprise a CDRH1 sequence of amino acids 31 to 35 (TYAMH) of SEQ ID NO: 4 or SEQ ID NO: 6, wherein one of these amino acids may be substituted by a different amino acid residue.

The heavy chain of an antibody according to the invention may comprise a CDRH2 sequence of amino acids 50 to 68 (RIRTKSSNYATYYAASVKG) of SEQ ID NO: 4 or SEQ ID NO: 6, wherein one, two or three of these amino acids may be substituted by a different amino acid.

The heavy chain of an antibody according to the invention may comprise a CDRH3 sequence of amino acids 101 to 110 (DMGIRRQFAY) of SEQ ID NO: 4, wherein one, two or three of these amino acids may be substituted by a different amino acid.

The heavy chain of an antibody according to the invention may comprise a CDRH3 sequence of amino acids 101 to 110 (DMGQRRQFAY) of SEQ ID NO: 6, wherein one, two or three of these amino acids may be substituted by a different amino acid.

The light chain of an antibody according to the invention may comprise a CDRL1 sequence of amino acids 24 to 38 (RASESVDTFDYSFLH) of SEQ ID NO: 5 or SEQ ID NO: 7, wherein one, two or three of these amino acids may be substituted with a different amino acid.

The light chain of an antibody according to the invention may comprise a CDRL2 sequence of amino acids 54 to 60 (RASNLES) of SEQ ID NO: 5 or SEQ ID NO: 7, wherein one or two of these amino acids may be substituted with a different amino acid.

The light chain of an antibody according to the invention may comprise a CDRL3 sequence of amino acids 93 to 101 (QQSNEDPYT) of SEQ ID NO: 5 or SEQ ID NO: 7, wherein one or two of these amino acids may be substituted with a different amino acid.

The m14F128 antibody has a heavy chain as shown in SEQ ID NO: 8 and a light chain as shown in SEQ ID NO: 9. An antibody of the invention may comprise this variable heavy chain sequence and/or this variable light chain sequence. The m14F128 antibody has the CDR sequences shown at amino acids 31 to 35, 50 to 68 and 101 to 110 of SEQ ID NO: 8 and amino acids 24 to 38, 54 to 60 and 93 to 101 of SEQ ID NO: 9. An antibody of the invention may comprise 1, 2, 3, 4, 5 or all 6 of these CDR sequences.

The m14F113 antibody has a heavy chain as shown in SEQ ID NO: 10 and a light chain as shown in SEQ ID NO: 11. An antibody of the invention may comprise this variable heavy chain sequence and/or this variable light chain sequence. The m14F113 antibody has the CDR sequences shown at amino acids 31 to 35, 50 to 68 and 101 to 110 of SEQ ID NO: 10 and amino acids 24 to 38, 54 to 60 and 93 to 101 of SEQ ID NO: 11. An antibody of the invention may comprise 1, 2, 3, 4, 5 or all 6 of these CDR sequences. An antibody of the invention may comprise amino acids 101 to 110 of SEQ ID NO: 10.

The term “antigen” (Ag) refers to the molecular entity used for immunization of an immunocompetent vertebrate to produce the antibody (Ab) that recognizes the Ag. Herein, Ag is termed more broadly and is generally intended to include target molecules that are specifically recognized by the Ab, thus including fragments or mimics of the molecule used in the immunization process, or other process, e.g. phage display, used for generating the Ab.

The term “epitope”, as used herein, is defined in the context of a molecular interaction between an “antigen binding polypeptide”, such as an antibody (Ab), and its corresponding antigen (Ag). Generally, “epitope” refers to the area or region on an Ag to which an Ab specifically binds, i.e. the area or region in physical contact with the Ab. Physical contact may be defined through various criteria (e.g. a distance cut-off of 2-6 Å, such as 3 Å, such as 4 Å, such as 5 Å; or solvent accessibility) for atoms in the Ab and Ag molecules. A protein epitope may comprise amino acid residues in the Ag that are directly involved in binding to a Ab (also called the immunodominant component of the epitope) and other amino acid residues, which are not directly involved in binding, such as amino acid residues of the Ag which are effectively blocked by the Ab, i.e. amino acid residues within the “solvent-excluded surface” and/or the “footprint” of the Ab.

The term epitope herein comprises both types of binding region in any particular region of TREM-1 that specifically binds to a TREM-1 antibody. TREM-1 may comprise a number of different epitopes, which may include, without limitation, conformational epitopes which consist of one or more non-contiguous amino acids located near each other in the mature TREM-1 conformation and post-translational epitopes which consist, either in whole or part, of molecular structures covalently attached to TREM-1, such as carbohydrate groups.

The epitope for a given antibody (Ab)/antigen (Ag) pair can be described and characterized at different levels of detail using a variety of experimental and computational epitope mapping methods. The experimental methods include mutagenesis, X-ray crystallography, Nuclear Magnetic Resonance (NMR) spectroscopy, Hydrogen deuterium exchange Mass Spectrometry (HX-MS) and various competition binding methods; methods that are known in the art. As each method relies on a unique principle, the description of an epitope is intimately linked to the method by which it has been determined. Thus, depending on the epitope mapping method employed, the epitope for a given Ab/Ag pair may be described differently.

At its most detailed level, the epitope for the interaction between the Ag and the Ab can be described by the spatial coordinates defining the atomic contacts present in the Ag-Ab interaction, as well as information about their relative contributions to the binding thermodynamics. At a less detailed level, the epitope can be characterized by the spatial coordinates defining the atomic contacts between the Ag and Ab. At an even less detailed level the epitope can be characterized by the amino acid residues that it comprises as defined by a specific criteria such as the distance between or solvent accessibility of atoms in the Ab:Ag complex. At a further less detailed level the epitope can be characterized through function, e.g. by competition binding with other Abs. The epitope can also be defined more generically as comprising amino acid residues for which substitution by another amino acid will alter the characteristics of the interaction between the Ab and Ag.

In the context of an X-ray derived crystal structure defined by spatial coordinates of a complex between an Ab, e.g. a Fab fragment, and its Ag, the term epitope is herein, unless otherwise specified or contradicted by context, specifically defined as TREM-1 residues characterized by having a heavy atom (i.e. a non-hydrogen atom) within a distance of, eg., 4 Å from a heavy atom in the Ab.

From the fact that descriptions and definitions of epitopes, dependant on the epitope mapping method used, are obtained at different levels of detail, it follows that comparison of epitopes for different Abs on the same Ag can similarly be conducted at different levels of detail.

Epitopes described on the amino acid level, e.g. determined from an X-ray structure, are said to be identical if they contain the same set of amino acid residues. Epitopes are said to overlap if at least one amino acid is shared by the epitopes. Epitopes are said to be separate (unique) if no amino acid residue are shared by the epitopes.

Epitopes may also be defined indirectly, by means of comparing the binding kinetics of antibodies to wild type human TREM-1 with those of human TREM-1 variants that have alanine mutations in anticipated epitopes. Decreased affinity or abrogated binding of an antibody to variants of human TREM-1 in which an amino acid residue has been replaced with an alanine residue indicates that the mutated amino acid contributes to the interaction between said antibody and wild type human TREM-1. This approach provides a negative identification of the epitope. The method is compromised in effectively defining the epitope by the fact that protein misfolding or unfolding would give similar results as abrogation of interaction. The analysis can be complemented by comparative gain of function mutational analyses of an orthologous target protein (eg., cynomolgus monkey TREM-1), if a cross-reactive antibody exists. The comparison will define the epitope differences between the antibody that does not cross-react with, eg., cynomolgus monkey TREM-1 and the cross-reactive antibody.

Indirect identification of the epitope can also be provided by means of measuring antibody (or antibody fragment) binding to variants of the wild type antigen (TREM-1). If an antibody or fragment thereof binds, eg., human but not cynomolgus monkey TREM-1 and if said antibody or fragment thereof is capable of binding a partly humanised variant of cynomolgus monkey TREM-1 then this regained binding indicates that the substituted amino acid residue(s) is/are important for the interaction of the antibody with the antigen. In the same way, increased affinity for humanized variants of cynomolgus monkey TREM-1, of an anti-human TREM-1 antibody (or its Fab fragment) that has a weaker binding to cynomolgus monkey TREM-1 compared to human TREM-1, can provide information on the identity of residues composing the binding epitope.

The effect of the same mutations on any given cross-reactive antibody makes it possible to discriminate between possible protein misfolding (abrogated binding to both antibodies) and loss of interaction in human TREM-1 (binding to one of the antibodies and abrogated binding to the other antibody), whilst unambiguously providing information on the epitope differences between the antibody that does not cross-react and the cross reactive antibody on an amino acid level.

Antibodies of the current invention may be capable of binding variants of human TREM-1. Antibodies of the invention may be capable of binding K20A-hTREM-1-Cmyc2-His6 (SEQ ID NO: 13), as determined using, eg., surface plasmon resonance.

Antibodies of the current invention may be capable of binding variants of cynomolgus monkey TREM-1. Antibodies of the invention may be capable of binding A24T/Y28F/N30S/R32Q/P70H-cTREM-1-Cmyc2-His6 (SEQ ID NO: 14), as determined using, eg., surface plasmon resonance. Antibodies of the invention may be capable of binding A24T/Y28F/N30S/R32Q/E54K-cTREM-1-Cmyc2-His6 (SEQ ID NO: 15), as determined using, eg., surface plasmon resonance.

An antibody of the invention may be capable of specifically binding TREM-1, wherein said antibody is capable of specifically binding (i) at least one amino acid residue selected from the group consisting of the A21, T22, K23, L24, T25, E26, and (ii) at least one amino acid residue selected from the group consisting of the A49, S50, S51, Q52, K53, A54, W55, Q56, I57, I58, R59, D60, G61, E62, M63, P64, K65, T66, L67, A68, C69, T70, E71, R72, P73, S74, K75, N76, S77, H78, P79, V80, Q81, V82, G83, R84, I85 and (iii) at least one amino acid residue selected from the group consisting of the C113, V114, 1115, Y116, Q117, P118 and P119 of human TREM-1.

An antibody of the invention may be capable of specifically binding a polypeptide comprising amino acids D38 to F48 of SEQ ID NO: 1 (human TREM-1), as determined using, eg., HX-MS.

An antibody of the invention may have an epitope comprising one, two, three, four, five, six, seven or all of the amino acid residues D38, V39, K40, C41, D42, Y43, T44 and L45 of SEQ ID NO: 1 (human TREM-1) and one, two or all of the amino acid residues selected from the group consisting of the E46, K47 and F48 of SEQ ID NO: 1 (human TREM-1), as determined using, eg., HX-MS.

An antibody of the invention may have an epitope comprising one, two, three or all of the amino acid residues selected from the group consisting of the D42, E46, D92 and H93 of SEQ ID NO: 1 (human TREM-1), as determined using variants of TREM-1 and surface plasmon resonance.

An antibody of the invention may have an epitope comprising at least the amino acid residues E46 and/or D92 of SEQ ID NO: 1 (human TREM-1), as determined using variants of TREM-1 and surface plasmon resonance.

An antibody of the invention may further comprise one, two or all of the amino acid residues selected from the group consisting of the the L31, 186 and V101 of SEQ ID NO: 1 (human TREM-1).

An antibody of the invention may be capable of specifically binding a polypeptide comprising amino acid residues E19 to L26 of cynomolgus monkey TREM-1 (SEQ ID NO: 12), or the corresponding amino acids of SEQ ID NO: 21, as determined using, eg., HX-MS.

An antibody of the invention may be capable of specifically binding human TREM-1, wherein the epitope of said antibody comprises one, two, three, four, five, six, seven, eight, nine or all of the amino acid residues selected from the group consisting of the the V39, K40, C41, D42, Y43, L45, E46, K47, F48 and A49 of SEQ ID NO: 1. An antibody of the invention may be capable of specifically binding human TREM-1, wherein the epitope of said antibody comprises one, two, three, four, five, six, seven, eight, nine or all of the amino acid residues K40, D42, T44, L45, E46, K47, Y90, H91, D92, H93, G94, L95 and R97 of SEQ ID NO: 1.

An antibody of the invention may be capable of specifically binding human TREM-1, wherein the epitope of said antibody comprises the D42 of SEQ ID NO: 1. An antibody of the invention may be capable of specifically binding human TREM-1, wherein the epitope of said antibody comprises the E46 of SEQ ID NO: 1. The epitope of said antibody may comprise the V39, C41, D42, Y43, L45 of SEQ ID NO: 1. The epitope of said antibody may comprise the E46, K47 and A49 of SEQ ID NO: 1. The epitope of said antibody may further comprise the F48 of SEQ ID NO: 1. The epitope of said antibody may comprise the K40, D42, T44, L45, E46, K47, Y90, H91, D92, H93, G94, L95 and R97 of SEQ ID NO: 1.

The definition of the term “paratope” is derived from the above definition of “epitope” by reversing the perspective. Thus, the term “paratope” refers to the area or region on the Ab to which an Ag specifically binds, i.e. with which it makes physical contact to the Ag.

In the context of an X-ray derived crystal structure, defined by spatial coordinates of a complex between an Ab, such as a Fab fragment, and its Ag, the term paratope is herein, unless otherwise specified or contradicted by context, specifically defined as Ag residues characterized by having a heavy atom (i.e. a non-hydrogen atom) within a distance of 4 Å from a heavy atom in TREM-1.

The epitope and paratope for a given antibody (Ab)/antigen (Ag) pair may be identified by routine methods. For example, the general location of an epitope may be determined by assessing the ability of an antibody to bind to different fragments or variant TREM-1 polypeptides. The specific amino acids within TREM-1 that make contact with an antibody (epitope) and the specific amino acids in an antibody that make contact with TREM-1 (paratope) may also be determined using routine methods. For example, the antibody and target molecule may be combined and the Ab:Ag complex may be crystallised. The crystal structure of the complex may be determined and used to identify specific sites of interaction between the antibody and its target.

Antibodies that bind to the same antigen can be characterised with respect to their ability to bind to their common antigen simultaneously and may be subjected to “competition binding”/“binning”. In the present context, the term “binning” refers to a method of grouping antibodies that bind to the same antigen. “Binning” of antibodies may be based on competition binding of two antibodies to their common antigen in assays based on standard techniques such as surface plasmon resonance (SPR), ELISA or flow cytometry.

An antibody's “bin” is defined using a reference antibody. If a second antibody is unable to bind to an antigen at the same time as the reference antibody, the second antibody is said to belong to the same “bin” as the reference antibody. In this case, the reference and the second antibody competitively bind the same part of an antigen and are coined “competing antibodies”. If a second antibody is capable of binding to an antigen at the same time as the reference antibody, the second antibody is said to belong to a separate “bin”. In this case, the reference and the second antibody do not competitively bind the same part of an antigen and are coined “non-competing antibodies”.

Antibody “binning” does not provide direct information about the epitope. Competing antibodies, i.e. antibodies belonging to the same “bin” may have identical epitopes, overlapping epitopes or even separate epitopes. The latter is the case if the reference antibody bound to its epitope on the antigen takes up the space required for the second antibody to contact its epitope on the antigen (“steric hindrance”). Non-competing antibodies generally have separate epitopes.

An antibody of the invention may compete with mAb 0170 for binding to human TREM-1. An antibody of the invention may compete with mAb 0170 for binding to cynomolgus monkey TREM-1. In other words, an antibody of the invention may belong to the same “bin” as mAb 0170.

The term “binding affinity” herein refers to a measurement of the strength of a non-covalent interaction between two molecules, e.g. an antibody, or fragment thereof, and an antigen. The term “binding affinity” is used to describe monovalent interactions (intrinsic activity).

Binding affinity between two molecules, e.g. an antibody, or fragment thereof, and an antigen, through a monovalent interaction may be quantified by determination of the equilibrium dissociation constant (K_(D)). In turn, K_(D) can be determined by measurement of the kinetics of complex formation and dissociation, e.g. by the SPR method. The rate constants corresponding to the association and the dissociation of a monovalent complex are referred to as the association rate constant k_(a) (or k_(on)) and dissociation rate constant k_(d) (or k_(off)), respectively. K_(D) is related to k_(a) and k_(d) through the equation K_(D)=k_(d)/k_(a).

Following the above definition, binding affinities associated with different molecular interactions, such as comparison of the binding affinity of different antibodies for a given antigen, may be compared by comparison of the K_(D) values for the individual antibody/antigen complexes.

An antibody of the invention may bind human TREM-1 with an affinity (KD) that is 1×10⁻⁷M or less, 1×10⁻⁸M or less, or 1×10⁻⁹M or less, or 1×10⁻¹⁰M or less, 1×10⁻¹¹M or less, 1×10⁻¹²M or less or 1×10⁻¹³M or less, as determined using surface plasmon resonance. An antibody of the invention may bind cynomolgus monkey TREM-1 with an affinity (KD) that is 1×10⁻⁷M or less, 1×10⁻⁸M or less, or 1×10⁻⁹M or less, or 1×10⁻¹⁰M or less, 1×10⁻¹¹M or less, 1×10⁻¹²M or less or 1×10⁻¹³M or less, as determined using surface plasmon resonance.

The term “binding specificity” herein refers to the interaction of a molecule such as an antibody, or fragment thereof, with a single exclusive antigen, or with a limited number of highly homologous antigens (or epitopes). In contrast, antibodies that are capable of specifically binding to TREM-1 are not capable of binding dissimilar molecules. Antibodies according to the invention may not be capable of binding Nkp44.

The specificity of an interaction and the value of an equilibrium binding constant can be determined directly by well-known methods. Standard assays to evaluate the ability of ligands (such as antibodies) to bind their targets are known in the art and include, for example, ELISAs, Western blots, RIAs, and flow cytometry analysis. The binding kinetics and binding affinity of the antibody also can be assessed by standard assays known in the art, such as SPR.

A competitive binding assay can be conducted in which the binding of the antibody to the target is compared to the binding of the target by another ligand of that target, such as another antibody.

In another aspect, the present invention provides compositions and formulations comprising molecules of the invention, such as the TREM-1 antibodies, polynucleotides, vectors and cells described herein. For example, the invention provides a pharmaceutical composition that comprises one or more TREM-1 antibodies of the invention, formulated together with a pharmaceutically acceptable carrier.

Accordingly, one object of the invention is to provide a pharmaceutical formulation comprising such a TREM-1 antibody which is present in a concentration from 0.25 mg/ml to 250 mg/ml, such as a concentration of from 10 to 200 mg/ml, and wherein said formulation has a pH from 2.0 to 10.0, such as a pH of from 4.0 to 8.0. The formulation may further comprise one or more of a buffer system, a preservative, a tonicity agent, a chelating agent, a stabilizer and/or a surfactant, as well as various combinations thereof. The use of preservatives, isotonic agents, chelating agents, stabilizers and surfactants in pharmaceutical compositions is well-known to the skilled person. Reference may be made to Remington: The Science and Practice of Pharmacy, 19^(th) edition, 1995.

In one embodiment, the pharmaceutical formulation is an aqueous formulation. Such a formulation is typically a solution or a suspension, but may also include colloids, dispersions, emulsions, and multi-phase materials. The term “aqueous formulation” is defined as a formulation comprising at least 50% w/w water. Likewise, the term “aqueous solution” is defined as a solution comprising at least 50% w/w water, and the term “aqueous suspension” is defined as a suspension comprising at least 50% w/w water.

In another embodiment, the pharmaceutical formulation is a freeze-dried formulation, to which the physician or the patient adds solvents and/or diluents prior to use.

In a further aspect, the pharmaceutical formulation comprises an aqueous solution of such an antibody, and a buffer, wherein the antibody is present in a concentration from 1 mg/ml or above, and wherein said formulation has a pH from about 2.0 to about 10.0.

The TREM-1 antibodies of the present invention and pharmaceutical compositions comprising such antibodies may be used for the treatment of inflammatory diseases such as the following: inflammatory bowel disease (IBD), Crohns disease (CD), ulcerative colitis (UC), irritable bowel syndrome, rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), psoriasis, psoriatic arthritis, systemic lupus erythematosus (SLE), lupus nephritis, type I diabetes, Grave's disease, multiple sclerosis (MS), autoimmune myocarditis, Kawasaki disease, coronary artery disease, chronic obstructive pulmonary disease, interstitial lung disease, autoimmune thyroiditis, scleroderma, systemic sclerosis, osteoarthritis, atoptic dermatitis, vitiligo, graft versus host disease, Sjogrens's syndrome, autoimmune nephritis, Goodpasture's syndrome, chronic inflammatory demyelinating polyneuropathy, allergy, asthma and other autoimmune diseases that are a result of either acute or chronic inflammation.

TREM-1 antibodies of the invention may be suitable for use in the treatment of individuals with inflammatory bowel disease. Inflammatory Bowel Disease (IBD) is a disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms. IBD primarily causes abdominal pain, diarrhea (which may be bloody), vomiting or weight loss, but may also cause complications outside of the gastrointestinal tract such as skin rashes, arthritis, inflammation of the eye, fatigue and lack of concentration. Patients with IBD can be divided into two major classes, those with ulcerative colitis (UC) and those with Crohn's disease (CD). CD generally involves the ileum and colon, it can affect any region of the intestine but is often discontinuous (focused areas of disease spread throughout the intestine). UC always involves the rectum (colonic) and is more continuous. In CD, the inflammation is transmural, resulting in abscesses, fistulas and strictures, whereas in UC, the inflammation is typically confined to the mucosa. There is no known pharmaceutical or surgical cure for Crohn's disease, whereas some patients with UC can be cured by surgical removal of the colon. Treatment options are restricted to controlling symptoms, maintaining remission and preventing relapse. Efficacy in inflammatory bowel disease in the clinic may be measured as a reduction in the Crohn's Disease Activity Index (CDAI) score for CD which is scoring scale based on laboratory tests and a quality of life questionnaire. In animal models, efficacy is mostly measured by increase in weight and also a disease activity index (DAI), which is a combination of stool consistency, weight and blood in stool.

TREM-1 antibodies of the invention may be suitable for use in the treatment of individuals with rheumatoid arthritis. Rheumatoid arthritis (RA) is a systemic disease that affects nearly if not all of the body and is one of the most common forms of arthritis. It is characterized by inflammation of the joint, which causes pain, stiffness, warmth, redness and swelling. This inflammation is a consequence of inflammatory cells invading the joints, and these inflammatory cells release enzymes that may digest bone and cartilage. As a result, this inflammation can lead to severe bone and cartilage damage and to joint deterioration and severe pain, among other physiologic effects. The involved joint can lose its shape and alignment, resulting in pain and loss of movement.

There are several animal models for rheumatoid arthritis known in the art. For example, in the collagen-induced arthritis (CIA) model, mice develop an inflammatory arthritis that resembles human rheumatoid arthritis. Since CIA shares similar immunological and pathological features with RA, this makes it a suitable model for screening potential human anti-inflammatory compounds. Efficacy in this model is measured by decrease in joint swelling. Efficacy in RA in the clinic is measured by the ability to reduce symptoms in patients which is measured as a combination of joint swelling, erythrocyte sedimentation rate, C-reactive protein levels and levels of serum factors, such as anti-citrullinated protein antibodies.

TREM-1 antibodies of the invention may be suitable for use in the treatment of individuals with psoriasis. Psoriasis is a T-cell mediated inflammatory disorder of the skin that can cause considerable discomfort. It is a disease for which there is currently no cure and it affects people of all ages. Although individuals with mild psoriasis can often control their disease with topical agents, more than one million patients worldwide require ultraviolet light treatments or systemic immunosuppressive therapy. Unfortunately, the inconvenience and risks of ultraviolet radiation and the toxicities of many therapies limit their long-term use. Moreover, patients usually have recurrence of psoriasis, and in some cases rebound shortly after stopping immunosuppressive therapy. A recently developed model of psoriasis based on the transfer of CD4+ T cells mimics many aspects of human psoriasis and therefore can be used to identify compounds suitable for use in treatment of psoriasis (Davenport et al., Internat. Immunopharmacol 2:653-672, 2002). Efficacy in this model is a measured by reduction in skin pathology using a scoring system. Similarly, efficacy in patients is measured by a decrease in skin pathology.

TREM-1 antibodies of the invention may be suitable for use in the treatment of individuals with psoriatic arthritis. Psoriatic arthritis (PA) is a type of inflammatory arthritis that occurs in a subset of patients with psoriasis. In these patients, the skin pathology/symptoms are accompanied by a joint swelling similar to that seen in rheumatoid arthritis. It features patchy, raised, red areas of skin inflammation with scaling. Psoriasis often affects the tips of the elbows and knees, the scalp, the navel and around the genital areas or anus. Approximately 10% of patients who have psoriasis also develop an associated inflammation of their joints.

The term “treatment”, as used herein, refers to the medical therapy of any human or other animal subject in need thereof. Said subject is expected to have undergone physical examination by a medical or veterinary medical practitioner, who has given a tentative or definitive diagnosis which would indicate that the use of said treatment is beneficial to the health of said human or other animal subject. The timing and purpose of said treatment may vary from one individual to another, according to many factors, such as the status quo of the subject's health. Thus, said treatment may be prophylactic, palliative, symptomatic and/or curative.

In terms of the present invention, prophylactic, palliative, symptomatic and/or curative treatments may represent separate aspects of the invention.

An antibody of the invention may be administered parenterally, such as intravenously, such as intramuscularly, such as subcutaneously. Alternatively, an antibody of the invention may be administered via a non-parenteral route, such as perorally or topically.

An antibody of the invention may be administered prophylactically. An antibody of the invention may be administered therapeutically (on demand).

EXEMPLARY EMBODIMENTS

1. A method of identifying a functional TREM-1 antibody, comprising (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell when said cell is incubated with a TREM-1 modifying agent; (c) contacting the culture of (b) with a TREM-1 antibody; and (d) measuring that the activity of the first cell is less than or more than the activity measured in (b). 2. A method of identifying a blocking TREM-1 antibody, comprising (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell when said cell is incubated with an activated neutrophil; (c) contacting the culture of the first cell and the activated neutrophil with a TREM-1 antibody; and (d) measuring that the activity of the first cell is less than the activity measured in (b). 3. The method of any one of embodiments 1-2, wherein the modifying agent of (b) is an activated neutrophil or a TREM-1 ligand. 4. A method of identifying a stimulating TREM-1 antibody, comprising (a) culturing a first cell expressing TREM-1, a signalling protein and a reporter construct; (b) measuring the activity of the first cell; (c) contacting/incubating said cell with a TREM-1 antibody; and (d) measuring that the activity of the first cell is more than the activity measured in (b). 5. The method of any one of embodiments 1-4, wherein the first cell is of haematopoetic origin. 6. The method according to embodiment 5, wherein the cell of haematopoetic origin is a myeloid cell. 7. The method according to embodiment 5, wherein the cell of haematopoetic origin is a T-cell. 8. The method according to any one of embodiments 1-7, wherein the signalling protein is DAP10. 9. The method according to any one of embodiments 1-7, wherein the signalling protein is DAP12. 10. The method according to any one of embodiments 1-7, wherein the signalling protein is TCR zeta. 11. The method according to any one of embodiments 1-7, wherein the signalling protein is Fc gamma RIII. 12. The method according to any one of embodiments 1-7, wherein the signalling protein is a Fc receptor. 13. The method according to any one of embodiments 1-6, wherein the reporter construct comprises a transcription factor and a reporter gene. 14. The method according to embodiment 13, wherein said transcription factor is NFAT. 15. The method according to embodiment 14, wherein said transcription factor is NFkB. 16. The method according to any one of embodiments 13-15, wherein said reporter gene encodes β-galactosidase. 17. The method according to any one of embodiments 13-15, wherein said reporter gene encodes luciferase. 18. The method according to any one of embodiments 13-15, wherein said reporter gene encodes green fluorescent protein (GFP). 19. The method according to any one of embodiments 13-15, wherein said reporter gene is a gene that encodes chloramphenicol transferase. 20. A method of identifying a blocking TREM-1 antibody, comprising (a) culturing a T-cell expressing TREM-1, DAP12 and a gene that encodes luciferase; (b) measuring the luminescence of the T-cell when it is incubated with an activated neutrophil; (c) contacting the co-culture of (b) with a TREM-1 antibody; and (d) measuring that the luminescence of the T-cell is less than the activity measured in (b). 21. The method according to embodiment 7, wherein said cell is a BWZ.36/hTREM-1:DAP12:NFAT-LacZ T-cell line. 22. The antibody identified by the method of any one of embodiments 1-3 and 5-21. 23. An antibody that is capable of specifically binding to TREM-1 and that is capable of blocking TREM-1 function. 24. The antibody according to any one of embodiments 22-23, wherein said antibody is capable of preventing or reducing the dimerisation/multimerisation of TREM-1. 25. The antibody according to any one of embodiments 22-24, wherein said antibody is capable of blocking the interaction between TREM-1 and its ligand. 26. The antibody according to any one of embodiments 22-25, wherein said antibody is capable of blocking PGLYRP1-induced TREM-1 function. 27. The antibody according to any one of embodiments 22-26, wherein the TREM-1 is human TREM-1. 28. The antibody according to embodiment 27, wherein said antibody is also capable of specifically binding to and blocking the function of TREM-1 from another species than a human. 29. The antibody according to embodiment 28, wherein the TREM-1 from another species is cynomolgus monkey TREM-1. 30. The antibody according to embodiment 28, wherein the TREM-1 from another species is rhesus monkey TREM-1. 31. The antibody according to any one of embodiments 22-30, which is capable of specifically binding K20A-hTREM-1-Cmyc2-His6 (SEQ ID NO: 13). 32. The antibody according to any one of embodiments 22-31, which is capable of specifically binding A24T/Y28F/N30S/R32Q/P70H-cTREM-1-Cmyc2-His6 (SEQ ID NO: 14). 33. The antibody according to any one of embodiments 22-32, which is capable of specifically binding A24T/Y28F/N30S/R32Q/E54K-cTREM-1-Cmyc2-His6 (SEQ ID NO: 15). 34. The antibody according to any one of embodiments 22-33, which competes with mAb 0170 for binding to human TREM-1. 35. The antibody according to any one of embodiments 22-34, which competes with mAb 0170 for binding to cynomolgus monkey TREM-1. 36. The antibody according to any one of embodiments 22-35, which is capable of specifically binding a polypeptide comprising amino acids D38 to F48 of SEQ ID NO: 1 (human TREM-1), as determined using, eg., HX-MS. 37. The antibody according to any one of embodiments 22-36, which has an epitope comprising one, two, three, four, five, six, seven or all of the amino acid residues selected from the group consisting of the D38, V39, K40, C41, D42, Y43, T44 and L45 of SEQ ID NO: 1 (human TREM-1) and one, two or all of the amino acid residues selected from the group consisting of the E46, K47 and F48 of SEQ ID NO: 1 (human TREM-1), as determined using, eg., HX-MS. 38. The antibody according to any one of embodiments 22-37, which is capable of specifically binding a polypeptide comprising amino acid residues E38 to L45 of cynomolgus monkey TREM-1, as determined using, eg., HX-MS. 39. The antibody according to any one of embodiments 22-38 which has an epitope comprising at least the amino acid residues selected from the group consisting of the D42, E46, D92 and H93 of SEQ ID NO: 1 (human TREM-1), as determined using surface plasmon resonance. 40. The antibody according to any one of embodiments 22-39 which has an epitope comprising at least the amino acid residues E46 and/or D92 of SEQ ID NO: 1 (human TREM-1), as determined using surface plasmon resonance. 41. The antibody according to any one of embodiments 22-40, wherein said antibody is capable of specifically binding (i) at least one amino acid residue selected from the group consisting of the A21, T22, K23, L24, T25, E26, and (ii) at least one amino acid residue selected from the group consisting of the A49, S50, S51, Q52, K53, A54, W55, Q56, I57, I58, R59, D60, G61, E62, M63, P64, K65, T66, L67, A68, C69, T70, E71, R72, P73, S74, K75, N76, S77, H78, P79, V80, Q81, V82, G83, R84, 185 and (iii) at least one amino acid residue selected from the group consisting of the C113, V114, I115, Y116, Q117, P118 and P119 of human TREM-1. 42. The antibody according to any one of embodiments 22-40, wherein said antibody is capable of specifically binding (i) at least one amino acid residue selected from the group consisting of the V39, K40, C41, D42, Y43, T44, L45, E46, K47, F48, A49, S50, S51, Q52, K53, A54, W55, Q56, and (ii) at least one amino acid residue selected from the group consisting of the T70, E71, R72, P73, S74, K75, N76, S77, H78, P79, V80, Q81, V82, G83, R84, I85 and (iii) at least one amino acid residue selected from the group consisting of the and C113, V114, 1115, Y116, Q117, P118, P119. 43. The antibody according to any one of embodiments 22-35, wherein said antibody is capable of specifically binding human TREM-1, wherein the epitope of said antibody comprises one, two, three, four, five, six, seven, eight, nine or all of the amino acid residues K40, D42, T44, L45, E46, K47, Y90, H91, D92, H93, G94, L95 and R97 of SEQ ID NO: 1. 44. The antibody according to any one of embodiments 22-35, wherein said antibody is capable of specifically binding human TREM-1, wherein the epitope of said antibody comprises the K40, D42, T44, L45, E46, K47, Y90, H91, D92, H93, G94, L95 and R97 of SEQ ID NO: 1. 45. The antibody according to any one of embodiments 22-44, the heavy chain of which comprises a CDRH3 sequence corresponding to amino acid residues 101 to 110 (DMGIRRQFAY) of SEQ ID NO: 4, wherein one, two or three of said amino acid residues may be substituted by a different amino acid. 46. The antibody according to any one of embodiments 22-44, the heavy chain of which comprises a CDRH3 sequence corresponding to amino acid residues 101 to 110 (DMGQRRQFAY) of SEQ ID NO: 6, wherein one, two or three amino acid residues may be substituted by a different amino acid. 47. The antibody according to any one of embodiments 45-46, further comprising a CDRH1 sequence corresponding to amino acid residues 31 to 35 (TYAMH) of SEQ ID NO: 4 or SEQ ID NO: 6, wherein one of these amino acid residues may be substituted by a different amino acid residue; and/or a CDRH2 sequence corresponding to amino acids 50 to 68 (RIRTKSSNYATYYAASVKG) of SEQ ID NO: 4 or SEQ ID NO: 6, wherein one, two or three of said amino acids may be substituted by a different amino acid residue. 48. The antibody according to any one of embodiments 45-47, the light chain of which comprises: a CDRL1 sequence corresponding to amino acid residues 24 to 38 (RASESVDTFDYSFLH) of SEQ ID NO: 5 or SEQ ID NO: 7, wherein one, two or three of these amino acid residues may be substituted with a different amino acid; and/or a CDRL2 sequence corresponding to amino acid residues 54 to 60 (RASNLES) of SEQ ID NO: 5 or SEQ ID NO: 7, wherein one or two of these amino acid residues may be substituted with a different amino acid; and/or a CDRL3 sequence corresponding to amino acid residues 93 to 101 (QQSNEDPYT) of SEQ ID NO: 5 or SEQ ID NO: 7, wherein one or two of these amino acid residues may be substituted with a different amino acid. 49. The antibody according to any one of embodiments 45-48, comprising SEQ ID NO: 4 or SEQ ID NO: 6 and/or SEQ ID NO: 5 or SEQ ID NO: 7. 50. The antibody according to any one of embodiments 22-49, which binds human TREM-1 with a binding affinity (KD) that is 1×10⁻⁷M or less, 1×10⁻⁹M or less, or 1×10⁻⁹M or less, or 1×10⁻¹⁰M or less, 1×10⁻¹¹M or less, 1×10⁻¹²M or less or 1×10⁻¹³M or less, as determined using surface plasmon resonance. 51. The antibody according to embodiment 50, wherein said binding affinity (KD) is 1×10⁻¹⁰M or less. 52. The antibody according to any one of embodiments 22-51, which binds cynomolgus monkey TREM-1 with a binding affinity (KD) that is 1×10⁻⁷M or less, 1×10⁻⁹M or less, or 1×10⁻⁹M or less, or 1×10⁻¹⁰M or less, 1×10⁻¹¹M or less, 1×10⁻¹²M or less or 1×10⁻¹³M or less, as determined using surface plasmon resonance. 53. The antibody according to embodiments 52, wherein said binding affinity is 1×10⁻⁹M or less. 54. The antibody according to any one of embodiments 22-53, which is an IgG. 55. The antibody according to any one of embodiments 22-54 for use as a medicament. 56. The antibody according to any one of embodiments 22-55 for the treatment of an autoimmune disease and/or chronic inflammation. 57. The antibody according to any one of embodiments 22-54 for the manufacture of a medicament for the treatment of an autoimmune disease and/or a chronic inflammation. 58. A method of treating an autoimmune disease and/or chronic inflammation comprising administering an antibody according to any one of embodiments 22-54 to a subject in need thereof. 59. The use according to any one of embodiments 55-57 or the method according to embodiment 58, wherein said autoimmune disease is rheumatoid arthritis. 60. The use according to any one of embodiments 55-57 or the method according to embodiment 58, wherein said autoimmune disease is Crohn's disease. 61. The use according to any one of embodiments 55-57 or the method according to embodiment 58, wherein said autoimmune disease is ulcerative colitis. 62. The use according to any one of embodiments 55-57 or the method according to embodiment 58, wherein said autoimmune disease is psoriatic arthritis. 63. The use according to any one of embodiments 55-57 or the method according to embodiment 58, wherein said autoimmune disease is juvenile idiopathic arthritis.

The present invention is further illustrated by the following examples which should not be construed as further limiting. The contents of all figures and all references, patents and published patent applications cited throughout this application are expressly incorporated herein by reference.

EXAMPLES Example 1: Generation of a BWZ.36 HumanTREM-1:DAP12 Stable Cell Line

The BWZ.36/hTREM-1:DAP12:NFAT-LacZ cell line (herein also referred to as the “BWZ/hTREM-1 reporter cell”) was derived from BW5147 T cells (Mus musculus thymus lymphoma cell line, ATCC TIB-47, LGC Standards, Middelsex, UK) and contains a LacZ reporter construct regulated by four copies of the NFAT promoter element (see Karttunen, J. & Shastri, N. (1991) Proc. Natl. Acad. Sci. USA 88, 3972-3976 and Fiering, S., Northrop, J. P., Nolan, G. P., Matilla, P., Crabtree, G. R. & Herzenberg, L. A. (1990) Genes Dev. 4, 1823-1834). TREM/DAP12/pMX-IRES vector (encoding 786 bp of TREM-1 from a SmaI site to BamHl site using TREM-1 cDNA (Gene Bank Ref. ID: NM_018643.2, Sino Biological Inc., Beijing, China) as template and oligo 5′ TAGTAGGGATCCGCTGGTGCACAGGAAGG (SEQ ID NO: 16) and 5′ TAGTAGGCGGCCGCTTCGTGGGCCTAGGGTAC (SEQ ID NO: 17) as primers cloned into pIREShyg vector GenBank Accession # U89672 (Cat. no. 6061-1, Clontech Laboratories, Calif., USA) was transfected in PLAT-E packaging cell line (provided by W. Yokoyama, Washington University; alternatively, Cat. no. RV-101, Cell Biolabs Inc, Bio-Mediator KY, Vantaa, Finland) using Superfect transfection reagent (Cat. no. 301305, Qiagen Nordic, Denmark). PLAT-E supernatants containing TREM/DAP12/pMX-IRES viral particles were used to infect BWZ.36 cells as follows: 2×10⁵ BWZ.36 cells were cultured in 6 well plates and the medium was replaced with 1.5 ml of supernatant containing the viral particles+8 mg/ml of polybrene. After 6-8 hours, 1.5 ml of normal medium was added to the plate and the cells were incubated for an additional 24 hours. BWZ.36 cell lines stably expressing TREM-1 were stained with anti TREM-1 monoclonal antibody (clone 21C7) and isolated by cell sorting.

Example 2: Cultivation of a BWZ.36 HumanTREM-1:DAP12 Stable Cell Line

BWZ/hTREM-1 reporter cell were cultured in RPMI 1640 w/o phenol red (Cat#11835, Gibco, Carlsbad Calif., USA), supplemented with 10% FCS (Cat#16140-071, Gibco, New York, USA), 1% Pen/Strep (Cat#15070-06, Gibco), 1 mM Sodium Pyruvate (Cat #11360, Gibco), 5 μM-2ME (Cat#31350-010, Gibco) and 2 mM L-Glutamine (Cat #25030, Gibco). No special plates or coating was required. 10 ml Versene (Cat #15040, Gibco) was added to detach the cells which then were transferred to tubes, centrifuged 1200 rpm 5 min and washed in fresh RPMI 1640 w/o phenol red. These cell were then ready to use in an assay or re-culture for further propagation.

Example 3: Immunisation of Mice and Identification of mAbs

In order to generate antibodies that bind human TREM-1, both wild type Balb/C mice and TREM-1 knock-out (KO) mice (C57BL/6 background) were immunised with either human (h) TREM-1 (SEQ ID NO:1), cells expressing hTREM-1 (BWZ.36 cells), or a combination of both. Primary screening was done either by means of direct ELISA on hTREM-1 protein or by means of FMAT, using BWZ.36 cells expressing hTREM-1. Secondary screening was done by flow cytometry on HEK293 cells expressing hTREM-1. Positive hybridoma supernatants were then screened in the BWZ/hTREM-1 reporter assay described in Example 4.

The highest number of blocking antibodies was obtained from KO mice immunised with hTREM-1 protein six times at two weeks intervals, followed by a booster injection. In total, over 200 hTREM-1 antibodies were isolated, of which approximately 70 were subsequently found to have a blocking effect.

All TREM-1 specific hybridoma supernatants were tested in the BWZ/hTREM-1 reporter assay first as supernantants and later as purified antibodies, in full titration from 5000 ng/ml down to 7 ng/ml, both as soluble and as platebound antibodies. Blood from a range of different donors was used as a source of fresh neutrophils. As an example, FIG. 4 shows antibodies from one fusion where the activity in the reporter assay as blocking activity is on the x-axis and the agonistic activity when the antibody is plate-bound is on the y-axis.

Example 4: Identification of PGLYRP1 as a Neutrophil-Expressed TREM-1 Ligand

PGLYRP1 was identified as a TREM-1 ligand through the use of immunoprecipitation coupled with mass spectroscopy (IP-MS). Soluble TREM-1 tetramer was used as an affinity “bait” molecule to identify a ligand. Briefly, TREM-1-tetramer-Fc (SEQ ID NO: 2) and separately CD83-Fc (SEQ ID NO: 5) were each incubated at final concentrations of 100 μg/ml with 270 million human neutrophils, purified by dextran sedimentation as described above, in 1 mL PBS at 4° C., 90 minutes with mild shaking. After pelleting these cells, the cells were resuspended in 1 mL PBS buffer with the inclusion of the crosslinker 3,3″-Dithiobis[sulfosuccinimidylpropionate] (DTSSP) (Thermo Scientific: 21578, Rockford, Ill., USA), at a concentration of 2 mM and incubated 30 minutes at room temperature. Cells were washed 3× with 1 mL PBS followed by lysis in 1 mL RIPA buffer (Thermo Scientific, 89901, Rockford, Ill., USA). The lysate was centrifuged at 15,000× g for 10 minutes at 4° C. to remove insoluble materials. Neutrophil proteins cross-linked to Fc coupled probes were immunoprecipitated from the supernatant using Protein A Mag Sepharose™ beads (GE Healthcare Life Sciences, 28-9670-56, Piscataway, N.J., USA). Briefly, 50 μL of beads were first washed with 200 μL PBS, then resuspended in 1 mL of cell lysate, incubated 60 minutes at 4° C., magnetically captured, and sequentially washed 2× with 200 μl RIPA buffer then 3× with 200 μL PBS. Upon removing PBS from the final magnetic capture, proteins were eluted from the magnetic beads using 200 μL buffer containing 8 M Urea, 100 mM Tris (pH 8.0), and 15 mM TCEP (Thermo Scientific, 77720, Rockford, Ill., USA) and incubated at room temperature for 30 minutes, beads were captured and supernatant was transferred to a Microcon Ultracel YM-30 filter (Millipore, 42410, Billerica, Mass., USA). Samples were spun at 14,000× g, 20° C., 30-60 minutes until no liquid remained on the top of the filter membrane. The retained proteins were then alkylated with 100 μL 50 mM IAA (iodoacetamide) in 8 M Urea for 30 minutes in dark at room temperature. The filter was washed 2× with 100 μL 50 mM NH₄HCO₃ and then transferred to a new collection tube. 1 μg trypsin (Promega, V5111, Madison, Wis.) in 60 μL 50 mM NH₄HCO₃ was added followed by incubation at 37° C. overnight. The tryptic digest was collected by centrifugation at 14,000 xg for 30 minutes followed by washing the filter with 50 μL 50 mM NH₄HCO₃. 10 μL of the digest was analyzed by LC/MS/MS using an LTQ-Orbitrap-XL mass spectrometer (Thermo Scientific, Waltham, Mass., USA). The data was searched against IPI human database (v3.81) using SEQUEST-Sorcerer engine (4.0.4 build) (SageN, Milpitas, Calif., USA) and then post processed with Scaffold 3 (Proteome Software, Portland, Oreg., USA) to filter protein IDs with a false discovery rate of 1%. After negative control subtraction, PGLYRP1 was found to be a high-confidence protein specifically associated with hTREM-1 tetramer. The immunoprecipitation in the neutrophils showed that out of the 148 identified proteins, 72 proteins were immunoprecipitated by the control construct (CD83) alone, 73 of the proteins were identical for TREM-1 and CD83, whereas only three were TREM-1 specific (FIG. 3). The experiment was subsequently repeated using neutrophils from a different donor and PGLYRP1 was again identified as specifically interacting with hTREM-1.

Example 5: Refolding and Purification of Human PGLYRP1 Expressed from E. coli

Human PGLYRP1 was expressed as inclusion bodies in Escherichia coli BL21 (DE3) cells. Bacteria were harvested by centrifugation, resuspended in 50 mM Tris-HCl pH8.0, 500 mM NaCl, 5 mM EDTA, 0.5% Triton X-100 and disrupted by sonication. The insoluble pellet was washed three times with 50 mM Tris, pH 8.0, 1% TritonX-100, 2 M urea and once with 50 mM Tris pH 8.0, then solubilized in 50 mM Tris-HCl, 6M guanidine hydrochloride, pH7.4, 1 mM DTT (final protein concentration 20 mg/ml). For in vitro folding, solubilized human PGLYRP1 inclusion bodies were diluted into 50 mM Tris, pH 8.0, 2 mM EDTA, 5 mM cysteamine, 0.5 mM cystamine, 0.4 M arginine (final protein concentration 1 mg/ml). After overnight at 4° C., the folding mixture was cleared by centrifugation/filtration and then diluted 12 fold into 10 mM MES pH 3.5 to lower the conductivity and pH (final pH˜5.8, conductivity˜6 mS/cm). The diluted folding mixture was then applied to a Hitrap SP HP 5 ml column (17-1151-01 GE Healthcare, Uppsala, Sweden), followed by a 5 column volume wash with 50 mM MES pH 5.8. The bound human PGLYRP1 was then eluted with a 0˜60% linear gradient of 50 mM MES pH 5.8, 1 M NaCl in 20 column volume. The fractions containing refolded human PGLYRP1 were pooled and concentrated to less than 4 ml by Amicon ultra 15 centrifugal units ((UFC800324 3,000 kDa MWCO, Millipore, Hellerup, Denmark). A Hiload 26/60 Superdex 75 318 ml column ((17-1070-01 GE Healthcare, Uppsala, Sweden) was then used to polish and buffer-exchange the proteins to Phosphate Buffered Saline (PBS). Majority of refolded human PGLYRP1 proteins was in monomer form. After concentrating, the final protein concentration was determined by measuring 280 nm absorbance with a NANODROP UV spectrometer. Protein purity was assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).

Example 6: Creation of a TREM-1 Responsive Reporter Assay

The TREM-1 reporter cell line was generated by transfecting the BWZ.36 cell line with a NFAT-LacZ reporter construct, as well as hTREM-1 and DAP12 (as described in Example 1). Neutrophils of healthy donors were purified by means of Dextran sedimentation. Blood was stratified on FicollPaque (17-0840-03, GE Healthcare, Piscataway, N.J., USA) gradient with a rate of 3 parts of Ficoll and 4 parts of blood in a 50 ml tube, then centrifuged at 400 xg for 30 minutes at 22° C., without brake. The intermediate PBMC band was gently removed by aspiration. The neutrophils stratified on the packed RBC were aspirated and transferred to a 50 ml polypropylene tube. The neutrohils and contaminating RBCs were diluted to 40 ml with 1×PBS and followed by addition of 10 ml 4% DEXTRAN 500 (Sigma, 31392, St Louis, Mo., USA) in PBS solution. After mixing by gentle inversion, the tubes were left at 22° C. for 20-30 min. A granulocyte rich supernatant was then transferred into a fresh tube and centrifuged at 250× g, 5 min, 22° C.; the supernatant was aspirated and discarded. Contaminating RBCs were removed with an osmotic lysis, briefly, the cell pellet was resuspended in 7.5 ml of 0.2% NaCl; gently mixed for 55-60 seconds and 17.5 ml of a 1.2% NaCl. solution was added. The volume was then brought to 50 ml with PBS and spun at 250× g for 5 min, the pellet was resuspended in 7.5 ml of 0.2% NaCl to repeat the lysis a second time. The final granulocyte pellet was resuspended in RPMI/10% FBS. These neutrophils were stimulated with PGN (InVivogen, tlrl-pgnsa, San Diego, Calif., USA) overnight to generate activated neutrophils able to stimulate TREM-1. The BWZ/hTREM-1 reporter cells were then added to the PGN activated neutrophil cultures in a 1:3 ratio of reporter cell:neutrophils. Instead of activated neutrophils, a TREM-1 ligand complex consisting of PGLYRP1 (SEQ ID NO: 23) and PGN could be used to stimulate TREM-1. The assay was run in Poly-D-Lysine coated Black cell culture plates (no. 356640 from BD Biosciences, San Jose, Calif., USA). TREM-1 activation was read out after 24 hours of culture using the BetaGlo reagent (E4720 from Promega, Madison, Wis., USA) and luminescence measured using a TopCount Luminescence counter from Perkin Elmer. As positive control TREM-1 could be activated by a plate-bound TREM-1 antibody (R&D MAB1278, Minneapolis, Minn., USA) able to agonise TREM-1. Plates were coated with isotype control or TREM-1 antibody MAB1278 (3 ug/ml in PBS, 100 ul/well) in the fridge O/N or for 2 hr at 37° C., 5% CO2 before the BWZ/hTREM-1 reporter cells were added. After 6-24 hours incubation TREM-1 activation could be read using the BetaGlo reagent (E4720 from Promega, Madison, Wis., USA) and luminescence measured using a TopCount Luminescence counter from Perkin Elmer. This BWZ.36/hTREM-1:DAP12:NFAT-LacZ cell line (the “BWZ/hTREM-1 reporter cell”) showed to be highly responsive to antibody-mediated cross linking of TREM-1, giving a ˜40-fold induction of the NFAT-driven LacZ production when stimulated with 1-10 μg/ml plate bound commercially available anti-TREM-1 antibody, as compared to the isotype control (FIG. 1). When stimulated with a toll-like receptor cocktail (tlrl-kit2hm, Invivogen, Sigma-Aldrich Denmark) alone (BWZ+TLR) no increase in signal was observed. Furthermore, unactivated neutrophils could not stimulate TREM-1, whereas TLR agonist cocktail (tlrl-kit2hm, Invivogen, Sigma-Aldrich Denmark) activated netrophils could stimulate the BWZ/hTREM-1 reporter cell.

Table 1, below, shows that TREM-1 antibodies disclosed herein are able to block the ligand-induced TREM-1 activation in such BWZ/hTREM-1 reporter cell assay.

TABLE 1 Antibody Luminescence × 10E6 BWZ + activated neutrophils 8.8 MAB1278 10 HPA 7.9 TREM26 9.9 TREM37 6.1 14F128 0.3 14F69 0.4 14F116 0.7 14F11 0.4 14F113 0.3

None of the tested commercial available antibodies: MAB1278 (cat. no. MAB1278, R&D Systems, Minneapolis, Minn. 55413, USA), anti-TREM-1 HPA (cat. no. HPA005563, Sigma, St Louis, Mo., USA), TREM26 (cat. no. 314902, Biolegend, San Diego, Calif. 92121, USA) and TREM37 (cat. no. 316102, Biolegend, San Diego, Calif. 92121, USA) were able to block the TREM-1 signal.

Example 7: Epitope Mapping Using HX-MS

Materials

Protein batches used were:

hTREM-1: human recombinant TREM-1, non-glycosylated, produced in E. coli. (cat. no. PRO-457, ProSpec-Tany TechnoGene Ltd., Rehovot, Israel).

TABLE 2 mAbs used Antibody Supplier mAb 0023 — mAb 0024 — mAb 0025 — mAb 0026 — MAB1278 RnD Systems TREM26 BioLegend

All proteins were buffer exchanged to PBS pH 7.4 before experiments.

Methods: HX-MS Experiments

Instrumentation and Data Recording

The HX experiments were automated by a Leap robot (H/D-x PAL; Leap Technologies Inc.) operated by the LeapShell software (Leap Technologies Inc.), which performed initiation of the deuterium exchange reaction, reaction time control, quench reaction, injection onto the UPLC system and digestion time control. The Leap robot was equipped with two temperature controlled stacks maintained at 20° C. for buffer storage and HX reactions and maintained at 2° C. for storage of protein and quench solution, respectively. The Leap robot furthermore contained a cooled Trio VS unit (Leap Technologies Inc.) holding the pre- and analytical columns as well as the pepsin column, the LC tubing and switching valves at 1° C. The switching valves of the Trio VS unit have been upgraded from HPLC to Microbore UHPLC switch valves (Cheminert, VICI AG). For the inline pepsin digestion, 100 μL quenched sample containing 200 pmol hTREM-1 was loaded and passed over the Poroszyme® Immobilised Pepsin Cartridge (2.1×30 mm (Applied Biosystems)) using a isocratic flow rate of 200 μL/min (0.1% formic acid:CH₃CN 95:5). The resulting peptides were trapped and desalted on a VanGuard pre-column BEH C18 1.7 μm (2.1×5 mm (Waters Inc.)). Subsequently, the valves were switched to place the pre-column inline with the analytical column, UPLC-BEH C18 1.7 μm (2.1×100 mm (Waters Inc.)), and the peptides separated using a 9 min gradient of 15-35% B delivered at 200 μl/min from an AQUITY UPLC system (Waters Inc.). The mobile phases consisted of A: 0.1% formic acid and B: 0.1% formic acid in CH₃CN. The ESI MS data, and the separate data dependent MS/MS acquisitions (CID) and elevated energy (MS^(E)) experiments were acquired in positive ion mode using a Q-TOF Premier MS (Waters Inc.). Leucine-enkephalin was used as the lock mass ([M+H]⁺ ion at m/z 556.2771) and data was collected in continuum mode (For further description of the set-up, see Andersen and Faber, Int. J. Mass Spec., 302, 139-148 (2011)).

Data Analysis

Peptic peptides were identified in separate experiments using standard CID MS/MS or MS^(E) methods (Waters Inc.). MS^(E) data were processed using BiopharmaLynx 1.2 (version 017). CID data-dependent MS/MS acquisition was analyzed using the MassLynx software and in-house MASCOT database.

HX-MS raw data files were subjected to continuous lock mass-correction. Data analysis, i.e., centroid determination of deuterated peptides and plotting of in-exchange curves, was performed using prototype custom software (HDX browser, Waters Inc.) and HX-Express ((Version Beta); Weis et al., J. Am. Soc. Mass Spectrom. 17, 1700 (2006)). All data were also visually evaluated to ensure only resolved peptide isotopic envelopes were subjected to analysis.

Epitope Mapping Experiment

Amide hydrogen/deuterium exchange (HX) was initiated by a 6-8 fold dilution of hTREM-1 in the presence or absence of mAb into the corresponding deuterated buffer (i.e. PBS prepared in D₂O, 96% D₂O final, pH 7.4 (uncorrected value)). All HX reactions were carried out at 20° C. and contained 4 μM hTREM-1 in the absence or presence of 4 μM mAb thus giving a 2 fold molar excess of mAb binding sites. At appropriate time intervals ranging from 10 sec to 10000 sec, 50 μl aliquots of the HX reaction were quenched by 50 μl ice-cold quenching buffer (1.35M TCEP) resulting in a final pH of 2.5 (uncorrected value).

Results and Discussion

This experiment maps the epitopes of mAbs 0023, 0024, 0025, 0026 and the commercial mAbs MAB1278 (RnD Systems) and Clone26 (Biolegend) on hTREM-1. The HX time-course of 43 peptides, covering 94% of the primary sequence of hTREM-1, were monitored in the absence or presence of the eight different mAbs for 10 to 10000 sec.

Exchange protection observed in the early time-points, e.g. <300 sec, relate to surface exposed amide protons and thus also relate to protein interfaces. In contrast, effects observed late in the time course are related to slow exchanging amide hydrogens and thus related to the structural core of the protein. Therefore, epitope effects appear in the early time points whereas structural stabilization effects will manifest as exchange reduction in late time points (Garcia, Pantazatos and Villareal, Assay and Drug Dev. Tech. 2, 81 (2004); Mandell, Falick and Komives, Proc. Natl. Acad. Sci. USA, 95, 14705 (1998)).

The observed exchange pattern in the early timepoints in the presence or absence of a given mAb can be divided into two different groups: One group of peptides display an exchange pattern that is unaffected by mAb binding. In contrast, another group of peptides in hTREM-1 show protection from exchange upon mAb binding. For example at 100 sec exchange with D₂O, approx than 2 amides are protected from exchange in the region Y111-F126 of mAb 0023. Regions displaying such protection effects are assigned to the epitope region.

Epitope Mapping of mAbs 0023 and 0026

mAbs 0023 and 0026 both induce identical alterations in the exchange profile of hTREM-1 and will be described together here. The regions displaying protection upon 0023/0026 binding encompass peptides covering residues T22-L96 and Y111-D127. However, by comparing the relative amounts of exchange protection within each peptide upon binding mAb 0023/0026 and the lack of epitope effects in peptides T25-F48, R84-Q112 and peptides starting at P118, the epitope can be narrowed to residues A21-E26, A49-I85 and C113-P119. Although distant in sequence, these regions are close in the 3D structure of hTREM-1.

Epitope Mapping of mAb 0024 and Biolegend Clone 26

mAb 0024 and Clone26 from Biolegend both induce identical alterations in the exchange profile of hTREM-1 and will be described together here. The regions displaying protection upon mAb 0024 binding encompass peptides covering residues V101-Q112. By comparing the relative amounts of exchange protection within each peptide upon binding mAb 0024 and the lack of epitope effects in surrounding peptides, the epitope can be narrowed to residues Q104-Q112 (FIG. 7B).

Epitope Mapping of NNC mAb 0025

The regions displaying protection upon 0025 binding encompass peptides covering residues D38-M63, T70-L96 and Y111-D127 (FIG. 7C). However, by comparing the relative amounts of exchange protection within each peptide upon binding 0254-0025 and the lack of epitope effects in peptides in surrounding regions, the epitope can be narrowed to residues V39-Q56, T70-I85 and C113-P119. Although distant in sequence, these regions are close in the 3D structure of hTREM-1 (FIG. 8).

Epitope Mapping of MAB1278

The regions displaying protection upon MAB1278 binding encompass peptides covering residues T70-L96 and V101-Q112 (FIG. 7D). However, by comparing the relative amounts of exchange protection within each peptide upon binding MAB1278 and the lack of epitope effects in peptides in surrounding regions, the epitope can be narrowed to residues T70-I85 and Q104-Q112. Although distant in sequence, these regions are close in the 3D structure of hTREM-1.

The structural position of the epitopes of mAbs 0023/0026 and mAb 0025 are shown in FIG. 7A. The epitope of mAbs 0023 and 0026 seems to reside primarily in 8-sheets in the dimer interface of the hTREM-1 crystal structure dimer. The antagonism of these mAbs could be a result of preventing hTREM-1 dimerisation and thus signalling.

Example 8: Determination of the Interaction Interface Between TREM-1 and mAb 0170

Epitopes were mapped on both recombinant human and cynomolgus monkey TREM-1 (hTREM-1 and cTREM-1, respectively). The hTREM-1 construct used in this example comprises the residues M1-H140 (SEQ ID NO: 18) and the cTREM-1 construct comprises the residues M1-R180 of (SEQ ID NO: 12) with six histidine residues added to the C-terminus and using the amino acid numbering from wild-type hTREM-1. Throughout this example the amino acids of cTREM-1 are numbered according to the analogous residue in hTREM-1, as illustrated in FIG. 11. The numbering used in this example can be converted to the numbering in SEQ ID NO: 12 by subtracting 19 if the residue number is 58 or less and by subtracting 20 if the residue number is 60 or greater. As an example, the residue number E46 on cTREM-1 in this example corresponds to residue (46-19=27) E27 in SEQ ID NO: 12. The residue number on L96 on cTREM-1 in this example corresponds to residue (96−20=76) L76 in SEQ ID NO: 12.

Solutions of TREM-1, alone or in the presence of mAb 0170, were diluted 25-fold in 97% deuterated hepes buffer (20 mM hepes, 150 mM sodium chloride, pH 7.4). Non-deuterated controls were prepared by diluting into protiated hepes buffer. The hydrogen exchange experiments were performed on a waters HDX nanoAcquity ultra-high performance liquid chromatography (UPLC) system (Waters Corporation, Milford, Mass., USA) which included the HD-x PAL auto sampler (LEAP Technologies Inc., Carrboro, N.C., USA) for automated sample preparation. The LC tubing, pre- and analytical columns and switching valves were located in a chamber cooled to 0.3° C. The trypsin digestion column was stored at 15° C. Hydrogen exchange reactions were performed at 20° C. Mass analysis was performed online using a Waters SYNAPT G2 HDMS mass spectrometer.

A volume containing 100 pmol of human or cynomolgus TREM-1 (1.54-1.98 μl) with or without 120 pmol mAb 0170 was diluted into deuterated hepes buffer to a final volume of 50 μl. At the appropriate time intervals the entire volume was transferred to and quenched in 50 μl 1.35 mM Tris(2-carboxyethyl)phosphine adjusted to pH 2.4 and held at 3° C. 99 μl of the quenched solution was immediately injected and passed over a Porozyme immobilised pepsin column (2.1 mm×30 mm) (Applied Biosystems, Life Technologies Corporation, Carlsbad, Calif., USA) and trapped on a Waters VanGuard BEH C18 1.7 μm (2.1 mm×5 mm) column at 100 μl/min flowrate using a 5% (vol/vol) methanol and 0.1% formic acid mobile fase. The peptides were separated on a Waters UPLC BEH C18 1.7 μm (1.0 mm×100 mm) column using a 10-40% acetonitrile gradient containing 0.1% formic acid at a 40 μl/min flow-rate.

The mass spectrometer was operated in positive ion mode with ion mobility separation enabled. The electrospray conditions were 3.2 kV capillary, 25 V sample cone, and 4 V extraction cone offsets, 850 ml/min flow of nitrogen desolvation gas heated to 350° C. and 50 ml/min cone gas flow. The source block was heated to 120° C. Lock-mass correction data was acquired using the 1+ ion of Leucine-enkephalin (m/z 556.2771) as reference compound and applied during data analysis. For peptide identification MS_(E)-type experiments using trap collision offsets of 6 V (low-energy) and 50 V (elevated energy) were performed. Deuterated samples were analysed using the 6 V low energy trap collision offset only. For further details see Andersen, M. D., Faber, J. H., Int. J. Mass Spectrom. (2011), 302, 139-148.

The MS^(E)-data was analysed using Waters ProteinLynx Global Server 2.5 and peptides of hTREM-1 were identified that covered 80% of the protein sequence (Table 3) and peptides of cTREM-1 were identified that covered 100% of the protein sequence (Table 4). The HX-MS data files were analysed using Waters DynamX 1.0 that automatically applies lock-mass correction and determines the degree of deuterium incorporation in each peptide. In addition, all data was manually inspected to ensure correct peak assignment and calculation of deuterium incorporation.

Results

A list of the peptides and their exchange patterns is provided in Table 3.

When mAb 0170 bound hTREM-1, protection from exchange was observed in peptides covering the sequence from A21 to L96 and the epitope was consequently determined to be within this region. When taking into account peptides that show no protection from exchange upon binding of mAb 0170, the epitope could be narrowed to the regions D38-F48. The region from R84-L96 showed little to no exchange in the presence or the absence of mAb 0170 and it was not possible to conclude whether this region was part of the mAb 0170 binding epitope. The peptide K47-A68 didn't show protection from exchange upon binding of mAb 0170, but the peptide T44-C69 was protected when mAb 0170 was bound. The first two residues of a peptide back-exchanges quickly and exchange information for those residues is lost. It was concluded that at least one of the residues E46, K47, and F48 was important for the binding of mAb 0170.

TABLE 3 Results from HXMS epitope mapping of mAb 0170 on human TREM-1 Peptide mAb 0170 A21-L37 N A21-D38 N A21-V39 N A21-C69 EX T22-D38 N D38-Q56 EX D38-M63 EX D38-L67 EX D38-A68 EX D38-C69 EX V39-A68 EX V39-C69 EX D42-C69 EX T44-C69 EX K47-A68 N A49-C69 N I57-A68 N I57-C69 N I57-L87 N L67-L87 N A68-E88 N A68-L96 N C69-L87 N C69-L96 N T70-L87 N T70-E88 N T70-L96 N R84-L96 LE E88-L96 LE Q104-L110 N Y111-M124 N Y111-F126 N Y111-D127 N C113-F126 N V114-F126 N V114-D127 N I115-F126 N I115-D127 N EX: Epitope region indicated by hydrogen exchange protection upon antibody binding. (Exhange difference (EX) > 0.8 deuterons) W: Weak exchange due to structural effects (0.1 < EX < 0.8). N: No protection from exchange upon antibody binding. (EX < 0.1) LE: Low intrinsic exchange

mAb 0170 Epitope on cTREM-1

A list of the peptides and their exchange patterns is given in Table 4.

When mAb 0170 bound to cTREM-1, protection from exchange was observed in peptides covering the sequence from E38 to A68 and the epitope was consequently determined to be within this region. When taking into account peptides that show no protection from exchange upon binding of mAb 0170, the epitope could be narrowed to the regions E38-L45. This epitope corresponded well with the mAb 0170 epitope on hTREM-1 but was truncated by three residues. The peptide C44-T69 in hTREM-1 was protected upon binding of mAb 0170, but the peptides A44-L67 and A44-A68 that cover the corresponding sequence in cTREM-1 were not protected. Thus, whereas at least one of the residues E46, K47, and F48 in hTREM-1 contributed to the binding epitope the corresponding residues E46, K47, and Y48 were not involved in binding of mAb 0170 to cTREM-1.

TABLE 4 HXMS epitope mapping of mAb 0170 on cynomolgus TREM-1 Peptide mAb 0170 T21-L37 W L24-L37 W T25-L37 W T25-E38 W E38-L67 EX E38-A68 EX V39-L67 EX V39-A68 EX K40-L67 EX A44-L67 W A44-A68 W E46-L67 N K47-L67 N A68-L87 W A68-L96 W A68-Q97 W K69-L87 W K69-L96 W V82-L96 W E88-L96 LE E88-Q97 LE Q97-L103 N Q104-L110 N Y111-C130 W Y111-L131 W V114-L131 W I115-C130 W I115-L131 W L131-T180 W L131-V182 W V132-T180 W V132-V182 W Y152-T180 W V181-E189 N V181-H206 W I190-H206 N T193-H206 N V195-H206 N T196-H206 N D197-H206 N EX: Epitope region indicated by hydrogen exchange protection upon antibody binding. (Exhange difference (EX) > 0.8 deuterons) W: Weak exchange due to structural effects (0.1 < EX < 0.8). N: No protection from exchange upon antibody binding. (EX < 0.1) LE: Low intrinsic exchange

Example 9: Study of Interaction Kinetics for Anti TREM-1 Antibodies to Human and Cynomolgus TREM-1 by Surface Plasmon Resonance (SPR)

Binding studies were performed on a ProteOn Analyzer (BioRad) that measures molecular interactions in real time through surface plasmon resonance. Experiments were run at 25° C. and the samples were stored at 15° C. in the sample compartment. The signal (RU, response units) reported by the ProteOn is directly correlated to the mass on the individual sensor chip surfaces in six parallel flow cells. Anti-human Fc monoclonal or anti-murine Fc polyclonal antibody from Biacore human or mouse Fc capture kits were immobilized in horizontal direction onto flow cells of a GLM sensor chip according to the manufacturer's instructions. The final immobilization level of capture antibody was approximately 2600-6000 RU in different experiments. Capture of purified monoclonal mouse or recombinant expressed anti-hTREM-1 antibodies was conducted by diluting the antibodies to 5-10 nM into running buffer (10 mM Hepes 0.15 M NaCl, 5 mM EDTA, 0.05% surfactant P20, pH 7.4) and injected in vertical direction at 30 μl/min for 60 s, creating reference interspots adjacent to all flow cells with only anti-Fc antibody immobilized. This typically resulted in final capture levels of test antibodies of approximately 100-300 RU and Rmax values of analyte of 30-90 RU. Binding of hTREM-1 or cTREM-1 proteins was conducted by injecting analyte (antigen) over all flow cells in horizontal direction to allow for comparative analyses of binding to different captured anti-TREM-1 antibodies relative to binding to the reference interspot. hTREM-1 or cTREM-1 proteins was diluted serially 1:3 to 1.2-100 nM or into running buffer, injected at 100 μl/min for 250 s and allowed to dissociate for 600 s. The GLM surface was regenerated after each injection cycle of analyte via two 18 s injections of 10 mM Glycine, pH 1.7 and 50 mM NaOH at 100 μl/min. This regeneration step removed the anti-TREM-1 antibody and any bound TREM-1 protein from the immobilized capture antibody surface, and allowed for the subsequent binding of the next interaction sample pair. The regeneration procedure did not remove the directly immobilized anti-Fc capture antibody from the chip surface.

Binding affinity between antibodies and the antigen was quantified by determination of the equilibrium dissociation constant (K_(D)) determined by measurement of the kinetics of complex formation and dissociation. The rate constants corresponding to the association and the dissociation of a monovalent complex such as k_(a) (association rate) and k_(d) (dissociation rate) were retrieved by fitting data to 1:1 Langmuir model using the ProteOn evaluation software for data analysis. K_(D) is related to k_(a) and k_(d) through the equation K_(D)=k_(d)/k_(a). Binding curves were processed by double referencing (subtraction of reference surface signals as well as blank buffer injections over captured anti-TREM-1 antibodies) prior to data analysis. This allowed correction for instrument noise, bulk shift and drift during sample injections.

TABLE 5 Results from measurements of binding constants ka (association rate), kd (dissociation rate) and KD (equilibrium dissociation constant) for the interaction of human TREM-1 to different anti-TREM-1 monoclonal antibodies. ka mAb Clone Origin (1/(Ms) kd (1/s) KD (M) mAb 0023 5F8A1 Hybridoma 1.0E+05 2.2E−04 2.1E−09 mAb 0024 5F28A1 Hybridoma 7.8E+04 3.6E−04 4.6E−09 mAb 0025 5F19A1 Hybridoma 8.8E+05 8.5E−04 9.7E−10 mAb 0026 5F27A1 Hybridoma 6.2E+04 9.7E−05 1.5E−09 mAb 0030 5F17A1B2 Hybridoma 1.2E+05 4.2E−04 3.6E−09 mAb 0031 13F6A1 Hybridoma 1.2E+06 3.7E−03 3.1E−09 mAb 0032 13F10A1 Hybridoma 1.1E+06 2.1E−03 1.9E−09 mAb 0033 9F11A1 Hybridoma 7.8E+04 1.1E−03 1.5E−08 mAb 0034 14F17A1 Hybridoma 1.9E+05 1.9E−04 1.0E−09 mAb 0039 5F8A1 on Recombinant 8.9E+04 1.6E−04 1.8E−09 mIgG2aa mAb 0040 5F8A1 on mIgG1 Recombinant 9.3E+04 2.0E−04 2.2E−09 mAb 0041 5F27 on mIgG2aa Recombinant 7.9E+04 1.8E−04 2.3E−09 mAb 0042 5F27A1 Recombinant 8.5E+04 2.5E−04 2.9E−09 on mIgG1 mAb 0044 14F69A1 Hybridoma 1.5E+06 2.9E−04 2.0E−10 mAb 0045 13F14A1 Hybridoma 1.3E+06 3.2E−03 2.5E−09 mAb 0046 14F70A1 Hybridoma 9.3E+05 1.9E−04 2.1E−10 mAb 0048 14F11A1B1 Hybridoma 1.7E+06 3.9E−03 2.4E−09 mAb 0049 14F86A1 Hybridoma 8.8E+05 1.3E−03 1.5E−09 mAb 0051 5F24 Recombinant 6.8E+05 3.0E−03 4.5E−09 HC645/LC647 mAb 0054 14F128A1 Hybridoma 1.6E+06 3.8E−03 2.4E−09 mAb 0059 14F113/14F69 Recombinant 1.7E+06 5.2E−04 3.2E−10 mAb 0063 14F116A1B1 Hybridoma 1.0E+06 1.4E−03 1.4E−09 mAb 0064 14F20A1B1 Hybridoma 8.9E+05 1.3E−03 1.5E−09 mAb 0067 14F11A1B1 Recombinant 2.2E+06 3.9E−03 2.0E−09 mAb 0068 14F128/14F11 Recombinant 2.7E+06 3.9E−03 1.7E−09 mAb 0070 14F113/14F69 Recombinant 2.1E+06 4.3E−04 2.5E−10 mAb 0078 14F106A2 Hybridoma 9.8E+05 1.4E−03 1.5E−09 mAb 0079 14F29A1B1 Hybridoma 2.6E+05 1.2E−03 4.6E−09 mAb 0080 14F17A1B1 Hybridoma 2.7E+05 1.9E−04 7.1E−10 mAb 0083 14F116A1B1 Recombinant 1.0E+06 1.7E−03 1.7E−09 mAb 0090 14F113 fully Recombinant 2.1E+06 1.5E−03 7.7E−10 humanized mAb 0115 14F113HC/ Recombinant 1.8E+06 2.4E−02 1.6E−08 14F128LC mixed and humanized mAb 0120 14F113/14F69 hz Recombinant 2.2E+06 1.5E−03 6.7E−10 variant HC A78L mAb 0121 14F113/14F69 hz Recombinant 2.8E+06 1.7E−03 6.3E−10 variant HC T93V mAb 0122 14F113/14F69 hz Recombinant 2.5E+06 1.4E−03 6.0E−10 variant LC M4L mAb 0124 14F113/14F69 hz Recombinant 2.0E+06 1.2E−03 6.1E−10 variant LC G68R mAb 0170 14F113/14F69 hz Recombinant 2.9E+06 5.4E−04 1.9E−10 variant LC Q98I

TABLE 6 Results from measurements of binding constants ka (association rate), kd (dissociation rate) and KD (equilibrium dissociation constant) for the interaction of cynomolgus TREM-1 to different anti-TREM-1 monoclonal antibodies. mAb Clone Origin ka (1/(Ms) kd (1/s) KD (M) mAb 0048 14F11A1B1 Hybridoma 1.4E+05 1.7E−04 1.2E−09 mAb 0059 14F113A1B1C1 Recombinant 1.8E+05 1.2E−04 6.7E−10 mAb 0067 14F11A1B1 Recombinant 3.8E+05 1.7E−03 4.7E−09 mAb 0068 14F128/14F11 Recombinant 2.8E+05 3.4E−03 1.2E−08 mAb 0083 14F116A1B1 Recombinant No No No binding binding binding mAb 0090 14F113 fully Recombinant 1.4E+05 3.0E−04 2.1E−09 humanized mAb 0121 14F113 hz Recombinant 1.3E+05 1.3E−04 9.4E−10 variant HC T93V mAb 0122 14F113 hz Recombinant 1.7E+05 1.6E−04 9.7E−10 variant LC M4L mAb 0124 14F113 hz Recombinant 1.7E+05 2.0E−04 1.1E−09 variant LC G68R mAb 0170 14F113 hz Recombinant 2.5E+05 8.9E−04 3.6E−09 variant LC Q98I

Example 10: Humanisation of the Blocking TREM-1 mAb 14F69

The variable regions of two lead antibodies were obtained from cloning of hybridomas 14F128A1 and 14F113A1B1C1. Both antibodies were cloned using the SMARTER-RACE technique (Clontech). The humanization effort was performed as an iterative loop where CDR grafted antibodies were first affinity evaluated and then re-engineered to include more backmutations until an acceptable affinity was retained, using hybridoma purified antibodies as a benchmark. The CDR grafted antibodies were designed in silico and ordered from a commercial vendor (xww.genscript.com). Subsequent re-engineering of antibodies was performed using site directed mutagenesis (Stratagene). All antibodies were expressed in HEK293-6E cells in preparation for affinity testing. Below is a description of the main considerations for selection of appropriate human germline and test of backmutations. All numbering of variable regions used in this example refers to the Kabat numbering scheme.

-   -   >m14F128A1_H (CDRs marked with bold and underligned) (SEQ ID NO         8)     -   >m14F128A1_L (CDRs marked with bold) (SEQ ID NO 9     -   >m14F113A1B1C1_H (CDRs marked with bold) (SEQ ID NO 10)     -   >m14F113A1B1C1_L (CDRs marked with bold) (SEQ ID NO 11)

From an analysis of the sequences, the CDRs for m14F128A1 according to Kabats definition are:

-   -   >CDR_H1     -   TYAMH     -   >CDR_H2     -   RIRTKS [N/S] NYATYY [V/A] DSVKD     -   >CDR_H3     -   DMG [I/A] RRQFAY     -   >CDR_L1     -   RASESVD [S/T] F [G/D] [I/Y] SF [M/L] H     -   >CDR_L2     -   RASNLES     -   >CDR_L3     -   QQSNEDPYT

With the differences between m14F128A1 and m14F113A1B1C1 given as [m14F128A1/m14F113A1B1C1].

A 3D model of m14F128A1 was build using standard techniques in MOE [available from www.chemcomp.com] and all residues within 4.5 Å of the effective CDR regions (VH: 31-35B, 50-58, 95-102; VL: 24-34, 50-56, 89-97) were defined as mask residues. Mask residues are all potentially important for sustaining the binding in the CDRs.

The mask residues included positions 1-2, 4, 27-37, 47, 49-59, 69, 71, 73, 78, 92-103 for the heavy chain and positions 1-5, 7, 23-36, 46, 48-56, 58, 62, 67-71, 88-98 for the light chain.

Using germline searches of m14F128A1 and manual inspection, VH3_73 and JH4 were identified as being an appropriate human germline combination for the heavy chain and VKIV_B3 and JK2 were identified as the appropriate human germline combination for the light chain.

>VH3_13/JH4 EVQLVESGGGLVQPGGSLKLSCAASGFTFSGSAMHWVRQASGKGLEWVG RIRSKANSYATAYAASVKGRFTISRDDSKNTAYLQMNSLKTEDTAVYYC TR/YFDYWGQGTLVTVSS >VKIV_B3/JK2 DIVMTQSPDSLAVSLGERATINCKSSQSVLYSSNNKNYLAWYQQKPGQP PKLLIYWASTRESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQYY STP/YTFGQGTKLEIKR

Humanisation was then performed with the following rules:

-   -   Residues outside the mask were taken as human.     -   Residues inside the mask and inside the Kabat CDR were taken as         murine.     -   Residues inside the mask and outside the Kabat CDR with         mouse/germline consensus were taken as the consensus sequence.     -   Residues inside the mask and outside the Kabat CDR with         mouse/germline difference were subject to potential back         mutations.

Grafting the effective CDR regions of m14F128A1 into the germlines formed the basic humanisation construct of m14F128A1, hz14F128A1.

>hz14F128A1_H EVQLVESGGGLVQPGGSLKLSCAASGFTFS TYAMH WVRQASGKGLEWVG R IRTKSNNYATYYAASVKG RFTISRDDSKNTAYLQMNSLKTEDTAVYYCTR DMGIRRQFAY WGQGTLVTVSS >hz14F128A1_L DIVMTQSPDSLAVSLGERATINC RASESVDSFGISFMH WYQQKPGQPPKL LIY RASNLES GVPDRFSGSGSGTDFTLTISSLQAEDVAVYYC QQSNEDPY T FGQGTKLEIK >CDR_H1 TYAMH >CDR_H2 RIRTKSNNYATYYAASVKG >CDR_H3 DMGIRRQFAY >CDR_L1 RASESVDSFGISFMH >CDR_L2 RASNLES >CDR_L3 QQSNEDPYT

The only differences compared to the murine CDRs were in CDR_H2 (shown in bold). Any discrepancy between m14F128A1 and hz14F128A1 in a mask residue will create a potential backmutation and the list includes:

-   -   hz14F128A1_H: S30N, G49A, A78L, V93T     -   hz14F128A1_L: M4L, M58I, G68R

Furthermore, the close homology of m14F128A1 and m14F113A1B1C1 was used to suggest residues that could impact the affinity of hz14F128A1.

-   -   hz14F128A1_H: N53S, 198Q     -   hz14F128A1_L: S27D_T, G29D, I30Y, M33L

In order to investigate all potentially humanised mAbs all combinations of the above mutants were produced and tested.

The final humanised anti hTREM1 antibody (mAb 0170) derived from hybridoma 14F113 contains one LC framework-backmutation (M4L) and one HC CDR3 mutation (Q98I). The mutation in HC CDR3 was introduced based on an affinity-synergy-study with a highly homologous antibody named 14F128. The rationale for including both mutations is described below.

Affinity-Synergy Study of Antibody 14F128 and 14F113

The hybridoma antibodies 14F128 and 14F113 are highly homologous and derived from the same somatic recombination event. The two antibodies compete in hTREM1 binding with 14F113 having the highest affinity. In total the CDR grafted versions of the two antibodies differ in their CDR compositions by only six amino acids (four in LC CDR, and two in HC CDR). The six mutations, when comparing 14F113 to 14F128, are LC T27_(d)S, D29G, Y30I, L33M and HC S54N, Q98I. Although CDR grafted 14F128 had an affinity inferior to CDR grafted 14F113 it was investigated if a beneficial affinity effect from one or more of the six mutations was suppressed by the overall effect when all six mutations were present. All six mutations (except HC S54N) were therefore individually introduced in the CDR grafted 14F113 antibody and the antibodies were ranked by affinity. Two mutations (LC L33M and HC Q98I) were individually capable of improving the affinity of CDR grafted 14F113. A mutation of the HC at position Q98I gave rise to a particularly good affinity of the resultant antibody (mAb 0170).

Framework Backmutation Affinity Analysis

The mouse version of the 14F113 antibody had seven mutations that were potentially necessary to include as backmutations during humanisation. The potential backmutations in the HC and LC were S30N, G49A, A78L and T93V M4L, V58I, G68R, respectively. The seven backmutations were introduced individually in CDR grafted 14F113 and then ranked by affinity. Although several of the mutations were capable of improving affinity, only LC mutation M4L was selected for mAb 0170. The decision to include mutations was balanced against expression titer (HEK293 6E), affinity, and the total number of mutations.

Example 11: Study of Interaction Kinetics for TREM-1 Antibodies to hTREM-1 by Surface Plasmon Resonance (SPR): Comparison Between mAb 0170 and Commercially Available TREM-1 Antibodies

Binding studies were performed on a ProteOn Analyzer (BioRad) that measures molecular interactions in real time through surface plasmon resonance. Experiments were run at 25° C. and the samples were stored at 15° C. in the sample compartment. The signal (RU, response units) reported by the ProteOn is directly correlated to the mass on the individual sensor chip surfaces in six parallel flow cells. Commercially available antibodies included were Biolegend #314907, Biolegend #316102 (Biolegend, USA), Hycult Biotech HM2252 (Hycult Biotech, Netherlands), R&D #MAB1278 (R&D systems, United Kingdom), SC98Z12 (Santa Cruz Biotechnology, USA), Sigma #WH0054210m4, Sigma #SAB1405121 (Sigma-Aldrich Danmark A/S)

Anti-human Fc monoclonal or anti-murine Fc polyclonal antibody from Biacore human or mouse Fc capture kits were immobilized in horizontal direction onto flow cells of a GLM sensor chip according to the manufacturer's instructions. The final immobilization level of capture antibody was approximately 2600-6000 RU in different experiments. Capture of purified monoclonal mouse or recombinant expressed humanized anti-hTREM-1 antibodies was conducted by diluting the antibodies to 5-10 nM into running buffer (10 mM Hepes 0.15 M NaCl, 5 mM EDTA, 0.05% surfactant P20, pH 7.4) and injected in vertical direction at 30 μl/min for 60 s, creating reference interspots adjacent to all flow cells with only anti-Fc antibody immobilized. This typically resulted in final capture levels of test antibodies of approximately 100-300 RU and Rmax values of analyte of 30-90 RU. Binding of hTREM-1 or cTREM-1 proteins was conducted by injecting analyte over all flow cells in horizontal direction to allow for comparative analyses of binding to different captured anti-TREM-1 antibodies relative to binding to the reference interspot. hTREM-1 or cTREM-1 proteins was diluted serially 1:3 to 1.2-100 nM or into running buffer, injected at 100 μl/min for 210 s and allowed to dissociate for 600 s. The GLM surface was regenerated after each injection cycle of analyte via two injections of 10 mM Glycine, pH 1.7 and 50 mM NaOH at 100 μl/min. This regeneration step removed the anti-TREM-1 antibody and any bound TREM-1 protein from the immobilized capture antibody surface, and allowed for the subsequent binding of the next interaction sample pair. The regeneration procedure did not remove the directly immobilized anti-Fc capture antibody from the chip surface.

Binding affinity between antibodies and the antigen was quantified by determination of the equilibrium dissociation constant (K_(D)) determined by measurement of the kinetics of complex formation and dissociation. The rate constants corresponding to the association and the dissociation of a monovalent complex such as k_(a) (association rate) and k_(d) (dissociation rate) were retrieved by fitting data to 1:1 Langmuir model using the ProteOn evaluation software 3.1.0.6 for data analysis. Ko is related to k_(a) and k_(d) through the equation K_(D)=k_(d)/k_(a).

Binding curves were processed by double referencing (subtraction of reference surface signals as well as blank buffer injections over captured anti-TREM-1 antibodies) prior to data analysis. This allowed correction for instrument noise, bulk shift and drift during sample injections.

TABLE 7 Results from measurements of KD (equilibrium dissociation constant) for the interaction of human and cynomolgus TREM-1 to different anti-TREM-1 monoclonal antibodies. human TREM-1 cyno TREM-1 Antibody KD (M) KD (M) mAb 0170 2E−10 3E−09 Biolegend #314907 9E−10 4E−09 Biolegend #316102 8E−10 No binding Hycult Biotech HM2252 3E−09 No binding R&D #MAB1278 8E−09 No binding SC98Z12 3E−08 No binding Sigma #WH0054210m4 2E−08 No binding Sigma #SAB1405121 No binding No binding

Example 12: Competition Binding Studies of Anti-Human TREM-1 Monoclonal Antibodies by Surface Plasmon Resonance

SPR binding competition studies were performed with monoclonal mouse or recombinant expressed humanised anti-hTREM-1 antibodies in order to discriminate between different binding sites (epitopes). Commercially available antibodies included were Biolegend #314907 (Biolegend, USA) and SC98Z12 (Santa Cruz Biotechnology, USA). Anti hTREM-1 monoclonal antibodies that compete for the same or an overlapping binding site (epitope) on the antigen are not able to bind simultaneously to the antigen and are therefore assigned to the same “bin”. Anti-TREM-1 monoclonal antibodies that do not compete for the same or overlapping binding site on the antigen are able to bind simultaneously and are thus assigned to different “bins”. Experiments were performed with soluble, human TREM-1 extracellular domain as antigen.

All studies were run at 25° C., and the samples were stored at 15° C. in the sample compartment. Individual anti-TREM-1 monoclonal antibodies and an unrelated control monoclonal antibody were immobilised onto separate flow cells of a GLC sensor chip using a 1:1 mixture of 0.4 M EDAC [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride] and 0.1 M Sulfo-NHS [N-hydroxysulfosuccinimide]. Each antibody was diluted in 10 mM sodium acetate pH 5.0 to a concentration of 25 or 10 (SC98Z12 (80394)) μg/ml, and was immobilised to an individual flow cell at 30 μl/min for 240 s. The antibodies were immobilised to flow cells L1-L6 (including control). After immobilisation of the antibody, the active sites on the flow cell were blocked with 1 M ethanolamine. Immobilisations were performed with activation and deactivation in a horizontal direction creating interspot reference points without immobilised protein. The final immobilisation level of test antibodies ranged from approximately 1100 to 1300 RU in one experiment, except for one antibody (SC98Z12) where only 390 RU was immobilised. Recombinant human TREM-1 was diluted to 100 nM into running buffer (10 mM Hepes 0.15 M NaCl, 5 mM EDTA, 0.05% surfactant P20, pH 7.4). The antigen was injected over immobilised antibodies in horizontal direction at 30 μl/min for 300 s, allowing control of potential unspecific binding both to interspot references and immobilised control antibodies resulting in 150-600 RU captured TREM-1, except for to one antibody (SC98Z12) with low immobilisation level where only 4 RU was captured.

Each antibody (the same ones that had been immobilised) was injected over parallel flow cells in a horizontal direction to allow for comparative analysis of binding to hTREM-1 captured by the primary antibodies relative to binding to both the interspot references and the immobilised control antibodies. Each competing antibody was diluted to 100 nM and injected at 100 μl/min for 250 s. The GLC chip was regenerated after each injection cycle of analyte via two 18 s injections of 1M Formic acid pH 3.5, 3M MgCl2 and 50 mM NaOH at 100 μl/min. This regeneration step removed the TREM-1 antigen and any bound secondary antibody from the immobilised antibody surface, and allowed for the subsequent binding of the next test sample. The regeneration procedure did not remove the directly immobilised anti-TREM-1 test antibody (primary antibody) from the chip surface. Data analysis was performed with the ProteOn Manager™ 3.1.0.6 Software. Capture levels were assessed to ensure that the regeneration step provided a consistent binding surface throughout the sequence of injections. No significant non-specific binding of human TREM-1 neither to the interspot control surfaces nor to immobilised control antibody was observed. Binding curves were processed by subtraction of interspot control surface signals. This allowed correction for instrument noise and bulk shift during sample injections.

The competition results were reported as either positive or negative binding (Table 8). Positive (+) binding indicates that the competing antibody was capable of binding the hTREM-1 simultaneously with the primary antibody (i.e. they do not compete), and the primary and competing antibodies were consequently assigned to different epitope bins. Negative binding indicates that the competing antibody was unable to bind the hTREM-1 simultaneously with the primary antibody (i.e. they do compete), and the primary and competing antibodies were thus assigned to the same epitope bin. The response values in these experiments were significant and allowed for an unambiguous determination of epitope bins of the anti-TREM-1 monoclonal antibodies.

TABLE 8 Ability to bind (+) or to compete (−) for antibodies tested in SPR competition assay. SC98Z12 did not give high enough capture of TREM-1 to evaluate as primary antibody (*). Primary Biolegend mAb mAb Secondary #314907 SC98Z12 0048 0170 Biolegend #314907 − * + + SC98Z12 − * + + mAb 0048 + * − − mAb 0170 + * − −

MAb 0170 and mAb 0048 (purified from hybridoma 14F11, which is identical to 14F128) were shown to compete for binding to human TREM-1. Biolegend #314907 and SC98Z12 did not compete with any of these for human TREM-1 binding but competed with each other. These findings conclude that the first two (mAb 0048 and mAb 0170) belong to the same bin (Bin1) while Biolegend #314907 and SC98Z12 belong to another bin (Bin2).

Example 13: Kinetic Analysis of the Interaction Between Fab 0011 and Fab 0170 Binding to Mutated Versions of Human and Cynomolgus TREM-1

Interaction studies were performed by SPR to define differences in the epitopes for 0011 and 0170 anti-human TREM-1 antibodies on human TREM-1. By comparing binding kinetics to human TREM-1 variants with introduced Alanine mutations in known epitopes, as well as partly “humanised” variants of cynomolgus TREM-1, the latter since only mAb 0170 cross reacts with cynomolgus TREM-1, amino acid residues unique for respective epitope were identified.

The hTREM-1 extracellular domain alanine mutant constructs and partly humanised cynomolgus mutant constructs used in this study are summarised in Table 9. All constructs used were variants either of SEQ ID NO:19 (cynomolgus TREM-1 variants) or SEQ ID NO: 20 (human TREM-1 variants) and included a C-terminal-cmyc²-His⁶ tag for capture in SPR binding kinetics assay. Unless otherwise stated, sequences referred to in this example are numbered according to FIG. 11.

TABLE 9 TREM-1 variant Protein Mutations 0221 human TREM-1 Ala mut 1 D38A 0222 human TREM-1 Ala mut 2 K40A 0223 human TREM-1 Ala mut 3 D42A 0224 human TREM-1 Ala mut 4 T44A 0225 human TREM-1 Ala mut 5 E46A 0226 human TREM-1 Ala mut 6 K47A 0227 human TREM-1 Ala mut 7 S50A 0228 human TREM-1 Ala mut 8 R84A 0229 human TREM-1 Ala mut 9 Y90A 0230 human TREM-1 Ala mut 10 H91A 0231 human TREM-1 Ala mut 11 D92A 0232 human TREM-1 Ala mut 12 H93A 0233 human TREM-1 Ala mut 13 R97A 0234 human TREM-1 Ala mut 14 R99A 0235 human TREM-1 Ala mut 15 D127A 0236 human TREM-1 Ala mut 16 R128A 0237 human TREM-1 Ala mut 17 R130A 0238 cynomolgus TREM-1 wt — 0239 cynomolgus TREM-1 “partly A44T, Y48F, N50S, humanised” R52Q, E75K, P91H 0240 cynomolgus TREM-1 “partly A44A, Y48F, N50S, humanised with back mutation 1” R52Q, E75K, P91H 0241 cynomolgus TREM-1 “partly A44T, Y48Y, N50S, humanised with back mutation 2” R52Q, E75K, P91H 0242 cynomolgus TREM-1 “partly A44T, Y48F, N50N, humanised with back mutation 3” R52Q, E75K, P91H 0243 cynomolgus TREM-1 “partly A44T, Y48F, N50S, humanised with back mutation 4” R52R, E75K, P91H 0244 cynomolgus TREM-1 “partly A44T, Y48F, N50S, (SEQ ID humanised with back mutation 5” R52Q, E75E, P91H NO: 14) 0245 cynomolgus TREM-1 “partly A44T, Y48F, N50S, (SEQ ID humanised with back mutation 6” R52Q, E75K, P91P NO: 15) 0247 human TREM-1 wt —

Binding studies were performed on a ProteOn Analyzer that measures molecular interactions in real time through surface plasmon resonance. Experiments were run at 25° C. and the samples were stored at 15° C. in the sample compartment. The signal (RU, response units) reported by the ProteOn is directly correlated to the mass on the individual sensor chip surfaces in six parallel flow cells. Anti-His monoclonal antibody was immobilised onto 6 parallel flow cells of a GLM sensor chip using a 1:1 mixture of 0.4 M EDAC [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride] and 0.1 M Sulfo-NHS [N-hydroxysulfosuccinimide]. Antibody was diluted in 10 mM sodium acetate pH 5.0 to a concentration of 25 μg/ml, and was immobilised onto individual flow cells at 30 μl/min for 240 s. After immobilisation of the antibody, the active sites on the flow cells were blocked with 1 M ethanolamine. Immobilisation was performed with all steps in horizontal direction. The final immobilisation level of capture antibody was approximately 8000 RU in one experiment. Cell culture medium from HEK 293 cells expressing wild type or different mutated variants of human or cynomolgus TREM-1 ECD was diluted 40-60 times in running buffer (10 mM HEPES, 150 mM NaCl, 3 mM EDTA, 0.05% surfactant P20, pH 7.4). TREM-1 proteins were injected over immobilised anti-His capture antibody in the vertical direction at 30 μl/min for 60 s. This resulted in 50-250 RU captured TREM-1 and created interspot references with only immobilised capture antibodies but no captured TREM-1 in the horizontal direction. Each Fab was injected over parallel flow cells in the horizontal direction to allow for kinetic analysis of binding to TREM-1 variants captured by anti-His antibody. Prior to injection each Fab was diluted to 0, 5.5 (in one experiment), 16.7 and 50 nM in running buffer, and injected at 100 μl/min for 250 s (association time). The dissociation time following these injections was monitored for 10 minutes. The GLM chip was regenerated after each interaction cycle of TREM-1 and Fab via two 18 s injections of 10 mM Glycine and 50 mM NaOH at 100 μl/min. This regeneration step removed the TREM-1 variants and any bound Fab from the anti-His antibody surface, and allowed for the subsequent binding of the next interaction pair. The regeneration procedure did not remove the directly immobilised anti-His capture antibody from the chip surface.

In order to obtain kinetic data, such as ka (association rate), kd (dissociation rate) and KD (equilibrium dissociation constant), data analysis was performed using the ProteOn Manager™ 3.1.0.6 Software. Capture and binding levels of samples run in duplicates or triplicates were assessed to ensure that the regeneration step provided a consistent binding surface throughout the sequence of injections. No significant unspecific binding to interspot references with only immobilised capture antibody was observed. Binding curves were processed by subtraction of interspot control surface signals, as well as injection of running buffer. This allowed correction for instrument noise and bulk shift during sample injections. The affinity of 0170 Fab and 0011 Fab to different TREM-1 ECD variants where compared to the affinity to wild type human or cynomolgus TREM-1 ECD.

The level of binding 10 s after end of injection of Fab, normalised to level of captured TREM-1 variant, was also assessed in order to identify mutated versions with abrogated or very low binding. A decrease in affinity combined with significantly lower normalised binding level can indicate a disrupted folding due to introduced mutations. It should however be noted that changes in kinetics will also affect this value. Each binding curve was therefore visually inspected for conclusion (data not shown).

Results for human TREM-1 with alanine single mutations (Table 10) show that two positions (E46 and D92) were unique in that they decreased binding more than two-fold to 0170 Fab.

TABLE 10 Affinity of 0170 Fab and 0011 Fab to human TREM-1 with alanine mutations relative to human TREM-1 wt. Binding level of 0170 Fab and 0011 Fab 10 s after end of association, expressed as degree of theoretical maximum binding level. Normalised binding KD relative to 0247 (% Rmax theor) Construct Mutation 0170 Fab 0011 Fab 0170 Fab 0011 Fab 0247 — 1 1 44 41 0221 D38A 0.7 15.0 29 5 0222 K40A 0.9 No binding 43 1 0223 D42A 132.9 26.9 13 3 0224 T44A 1.2 1.8 46 40 0225 E46A 2.7 0.9 44 44 0226 K47A 1.0 1.1 40 38 0227 S50A 0.7 0.9 45 41 0228 R84A 0.5 1.3 15 8 0229 Y90A 0.5 2.9 40 31 0230 H91A 0.9 2.5 41 33 0231 D92A 9.2 1.1 34 41 0232 H93A 36.4 5.2 22 29 0233 R97A 1.1 6.2 36 22 0234 R99A 0.8 1.0 15 11 0235 D127A 1.1 0.8 43 41 0236 R128A 0.9 1.2 39 35 0237 R130A 1.0 0.8 35 34

mAb-0170 was, in contrast to mAb-0011, able to bind cynomolgus TREM-1. Humanisation of cynomolgus TREM-1 in the selected area did not result in regained affinity of 0177 compared to human TREM-1 (0247) indicating that other residues or combinations of residues are important for the differences in affinity for human and cynomolgus TREM-1.

0243 shows no binding to 0170 Fab or 0011 Fab. For this construct it cannot be excluded that mutations have affected the overall structure and therefore not be concluded if Q52 is involved in binding of the studied Fabs to human TREM-1.

TABLE 11 Affinity of 0170 Fab and 0011 Fab to wt cynomolgus TREM-1 ECD, partly humanised cynomolgus TREM-1 ECD variants and wt human TREM-1 ECD. Binding level of 0170 Fab and 0011 Fab 10 s after end of association, expressed as degree of theoretical maximum binding level. Normalised binding KD (M) (% Rmax theor) Construct 0170 Fab 0011 Fab 0170 Fab 0011 Fab wt cTREM-1 1E−09 No binding 39 0 0239 2E−09 >1 uM 19 1 0240 2E−09 >1 uM 28 0 0241 2E−09 >1 uM 26 2 0242 1E−09 >1 uM 21 1 0243 No binding No binding 5 1 0244 1E−09 No binding 7 0 0245 1E−09 No binding 34 0 0247 2E−10 1E−09 45 42

Example 14: mAb 0170 Efficiently Blocks TREM-1 Activation in the BWZ/hTREM-1 Reporter Cell Assay

The BWZ/hTREM-1 reporter cell assay described in Example 6 was used to calculate the potency of mAb 0170 in blocking TREM-1. BWZ/hTREM-1 reporter cells were stimulated with TREM-1 ligand complex and mAb 0170 added at various concentrations. FIG. 9 shows a dose-dependent blocking of the TREM-1 signal resulting in total block of the signal at concentrations higher than 0.2 ug/ml. The IC50 value was determined to be 2.4 nM using the Graphpad Prism software, equation: log(inhibitor) vs. response—Variable slope.

Example 15: Commercially Available TREM-1 Antibodies do not Block TREM-1 Activation in the BWZ/hTREM-1 Reporter Cell Assay

Multiple doses of antibody were included in the BWZ/hTREM-1 reporter cell assay, as described previously. SAB1405121 (clone 3F5 from Sigma Aldrich, St. Louis, Mo., USA), WH0054210M4 (clone 2E2 from Sigma Aldrich, St. Louis, Mo., USA), sc-80394 (clone 98Z12 from Santa Cruz, Calif., USA), HM2252 (clone 6B1 from Hycult biotech, 5405 PB UDEN, The Netherlands), 316102 (clone TREM-37 from Biolegend, San Diego, Calif. 92121, USA), and 314907 (clone TREM-26 from Biolegend, San Diego, Calif. 92121, USA), were not able to block the TREM-1 activity significantly, whereas mAb 0170 disclosed herein could block TREM-1 activity with more than 99% at 0.3 ug/ml. Isotype controls had >95% remaining reactivity even at 3 ug/ml.

TABLE 12 % % % % remaining remaining remaining remaining Anti TREM-1 activity at activity at activity at activity at clone 0 μg/ml 0.003 μg/ml 0.03 μg/ml 0.3 μg/ml SAB1405121 100 104 101 97 WHO054210M4 100 98 104 86 sc-80394 100 120 134 131 HM2252 100 96 122 113 316102 100 98 103 90 (0.09% azide) 314907 100 100 124 108 mAb 0170 100 96 80 0

Example 16: mAb 0170 Blocked Cynomolgus TREM-1

In order to test for functionality against TREM-1 from other species, mouse and cynomolgus monkey TREM-1 was transfected together with human and mouse DAP12, respectively, to generate a reporter cell assay as the one for human. This was essentially done as described for the human system (Examples 1, 2 and 6) but replacing humanTREM-1 with full length murine (m)TREM-1 (SEQ ID NO: 22) or full length cynomolgus monkey (c)TREM-1 (SEQ ID NO: 21). cDNA encoding cTREM-1 (SEQ ID NO: 22) was synthesized at GeneArt and cloned into pHLEF38 (licensed from CMC ICOS), in the XhoI-XbaI orientation. TE alpha NFAT Luc cells was co-transfected with pHLEF38.cynoTrem1 and pNEF38.NFlag hDAP12 using 10 ug of each plasmid and electroporated 8e6 cells in approx. 500 ul total volume (400 ul growth medium and 100 ul DNA) using the BTX electoporator (260 V, 1050 uF, 720 ohms; time constant was 23 msec). Cells were plated for 48 hours in a 10 cm plate, in 10 ml of 50% conditioned medium and plated directly into selection at 8e3 cells/well of a flat bottomed 96W plates (5 plates) in 200 ul/well of 30% conditioned medium with 800 ug/ml G418 and 0.5 mM L-histidinol. After 2 weeks of incubation, 40 single colonies were identified using the Genetix Clone Select Imager.

The only commercially available TREM-1 antibody able to cross react with cynomolgus monkey TREM-1 was 314907 (clone TREM-26 from Biolegend, San Diego, Calif. 92121, USA) (see Example 11). None of the commercially available antibodies tested in Example 15 were able to block the function of cynoTREM-1, not even the one that could bind to cynomolgus monkey TREM-1.

TABLE 13 % remaining cyno TREM-1 activity [mAb amount] mAb 0170 314907  0 ug/ml 100.00 100.00 0.74 ug/ml  7.97 103.97 20 ug/ml 0 87.72

Likewise, a reporter cell line with mouse TREM-1 was generated. None of the antibodies able to bind to human TREM-1 or to cynomolgus and human TREM-1 could cross-bind to mouseTREM-1. Thus, antibodies against mouseTREM-1 were generated essentially as described for generating human TREM-1 antibodies but with mouse TREM-1 as the antigen. These antibodies were screened for mouse TREM-1 binding and blocking function in the murine reporter gene assay. One such antibody (mAb 0174) was able to bind and block the mouse TREM-1 function.

Example 17: TNFalpha Release from M2 Macrophages that were Stimulated by PGLYRP-1 was Blocked by TREM-1 Antibodies

Those skilled in the art will recognize the value of establishing a freezer bank collection of primary cells from multiple donors thus providing for convenient replication of experiments. In vitro derived macrophages were produced from peripheral blood monocytes as follows. Negatively enriched monocytes were isolated from a peripheral blood “leukopak” obtained from Research Blood Components (Brighton, Mass., USA) using a Rosette Sep kit (cat. no. 15068) from Stem Cell Technologies (Vancouver, BC, Canada) following the manufacture instructions. Isolated monocytes were suspended in 10% DMSO/FBS aliquots of 50e6 cell/ml and gradually cooled to −80 C. To produce macrophage cells, one or more frozen vials of monocytes were rapidly thawed in a 37 C water bath, diluted to 10 ml with growth media [RPMI 1640 (Gibco, Carlsbad Calif., USA) cat. no. 72400-047) with 10% FBS (Fisher Scientific cat no 03-600-511] and centrifuged 5 minutes at 250 g. Cells were suspended to 2e6 cells/ml in growth media supplemented with 50 ng/ml human MCSF (Gibco cat. no. PHC9501), placed into tissue culture treated, petri style tissue culture plates and into a humidified incubator programmed to maintain a “hypoxic” atmosphere of 5% CO2, 2% O2. On the third day in culture, the cells were fed with the addition of an equal volume of growth media supplemented with 50 ng/ml human MCSF. After 6 days in culture the monocytes had differentiated into M0 macrophages. M0 cells were further differentiated by changing the media to growth media supplemented with 50 ng/ml human IFNg (Gibco cat no PHC4031) for M1 macrophages or 40 ng/ml human IL-4 (Gibco cat no PHC0045) for M2 macrophages and returning to the incubator for an additional 22 hours. On the seventh day, macrophages were suitably differentiated to be used in a bioassay. Briefly, macrophages were recovered from the petri plates by washing with 1×PBS, followed by 5 mM EDTA in PBS. The plates were then returned to 37 C for 30 minutes and cells were “power washed” off the plate using a 10 ml syringe and 22 G needle. Cells were then diluted into growth media, centrifuged at 250 g for 5 minutes after which the cell pellet was suspended to a final concentration of 1e6/ml.

Macrophage cells prepared as above were used in bioassays where cytokines such as TNF-alpha produced in response to stimulation of the cells with TREM-1 ligand were measured in the conditioned media by ELISA. Such a bioassay was further utilized to measure blockade of such TREM-1 ligand stimulation by TREM-1 specific antibodies. TREM ligand or negative controls were prepared at 4× concentrations and 50 microliters/well in growth media were added to 96 well microtiter dishes. Final concentrations of TREM-1 ligand consisted of 7.5 ng/ml recombinant human PGLYRP1 (see Example 5) and 3 μg/ml PGN-BS (Invivogen, tlrl-pgnbs, San Diego Calif., USA). Cells were cultured under humidified hypoxic conditions as described above for 22 hours after which conditioned media was collected and TNF-alpha levels were measured by ELISA, following manufacturer's instructions (R&D Systems, catalogue DY210, MN, USA). FIG. 10 shows that the TREM-1 antibodies decrease TNFalpha release from these stimulated M2 macrophages.

Table 12, below, shows the IC50 values from such experiment indicating that the antibodies disclosed herein are very potent in blocking the TREM-1 dependent cytokine release.

TABLE 14 Antibody (mAb) R square IC50, ng/ml 0122 0.99 14 0170 0.99 12 0090 0.99 21 0115 0.88 92

Example 18: TNFalpha Release from Cynomolgus Macrophages can be Blocked by mAb 0170

Peripheral blood derived macrophage serve as an excellent in vitro model in the study of innate immune modulation and activation. TREM-1 is known to play a key role in controlling this process. The use of the non-human primate species Macaca fascicularis, commonly known as Cynomolgus monkey is critical to understanding the in vivo effects of modulating TREM1 signalling. In this example anti-TREM-1 antibodies are tested for their ability to block production of cytokines in cynomolgus M2 macrophage cultures.

Macrophage cells were generated as follows. Whole blood was harvested from healthy male adult animals (SNBL, Everett Wash., USA) by venipuncture using sodium heparin vacutainer tubes (Cat No 3664870, Bectin Dickinson Franklin Lakes N.J., USA). Whole blood was diluted 30% with PBS, then 30 ml was carefully layered on to 15 ml of Ficoll-Paque (Cat No 17-1440-03 GE Healthcare, Uppsala Sweden) prediluted to 96% with PBS in a 50 ml conical tube. After centrifugation: 30 min, room temperature, 400 g with low acceleration and no brake; peripheral blood mononuclear cells (PBMC) were harvested from the Ficoll/plasma interphase, diluted 3× with PBS and centrifuged 7 minutes, room temperature, 200 g. Supernatant containing contaminating platelets was aspirated and discarded and the cell pellet was resuspended in 30 ml of PBS+0.2% FBS (fetal bovine serum). This cell wash process was repeated 2 additional cycles after which the PBMC cell pellet was resuspended in RPMI culture media (Cat No. 61870-036, Life Technologies, Grand Island N.Y., USA) plus 10% FBS to 2E6 cells/ml and dispensed onto 15 cm petri dishes (Cat No 430599 Corning, Tewksbury Mass., USA) at 20 ml/dish. Monocytes were allowed to adhere to plastic by incubating overnight at 37 C, 5% CO₂, 100% humidity after which non adherent cells were removed by gently swirling and rocking the plates for 20 seconds followed by aspiration. 20 ml of fresh growth media supplemented with 50 ng/ml hMCSF (Cat No. PHC9501, Life Technologies, Grand Island N.Y., USA) was added to each plate and placed into hypoxic culture conditions of 37 C, 5% CO₂, 2% O₂, 100% humidity for 7 days. On the third day in culture, the cells were fed with the addition of an equal volume of growth media supplemented with 50 ng/ml human MCSF. After 6 days in culture the monocytes had differentiated into M0 macrophages. M0 cells were further differentiated by changing the media to growth media supplemented with 50 ng/ml human IFNg (Gibco cat no PHC4031) for M1 macrophages or 40 ng/ml human IL-4 (Cat No. PHC0045, Life Technologies, Grand Island N.Y., USA) for M2 macrophages and returning to the incubator for an additional 22 hours. On the seventh day, macrophages were suitably differentiated to be used in a bioassay. Briefly, macrophages were recovered from the petri plates by washing with 1× PBS, followed by 5 mM EDTA in PBS. The plates were then returned to 37 C for 30 minutes and cells were “power washed” off the plate using a 10 ml syringe and 22 G needle. Cells were then diluted into growth media, centrifuged at 250 g for 5 minutes after which the cell pellet was suspended to a final concentration of 1e6/ml.

Macrophage cells prepared as above were used in bioassays where cytokines such as TNF-alpha produced in response to stimulation of the cells with TREM-1 ligand were measured in the conditioned media by ELISA. Such a bioassay was further utilized to measure blockade of such TREM-1 ligand stimulation by TREM-1 specific antibodies. TREM-1 ligand or negative controls were prepared at 4× concentrations and 50 microliters/well in growth media were added to 96 well microtiter dishes. Final concentrations of TREM-1 ligand consisted of 7.5 ng/ml recombinant human PGLYRP1 (generated as described in Example 5) and 3 μg/ml PGN-BS (Cat No. tlrl-pgnbs, Invivogen San Diego Calif., USA). Antibodies were added in 50 microliters/well of growth media followed by cells in 50 microliters/well of macrophage. Cells were cultured under humidified hypoxic conditions as described above for 22 hours after which conditioned media was collected and TNF-alpha levels were measured by ELISA, following manufacturer's instructions (Cat No. DY1070 R&D Systems, Minneapolis Minn., USA). The table following table shows TNFα values of M2 macrophage cultures stimulated with TREM-1 ligand (PGLYRP1+PGN) in the presence of control antibody or anti-TREM-1 antibody.

Donor 1 Donor 2 TNF-α, pg/ml TNF-α, pg/ml M2 macrophages with: Avg SD Avg SD Cells only 0.5 19.0 12.0 PGRP-S only 3.5 13.0 6.3 PGN BS only 5.7 2.8 22.4 3.8 PGN + PGRP-S 295.3 49.3 307.4 75.8 +Fc4 neg -3 248.5 54.0 285.0 57.6 +Fc4 neg -1 215.6 41.5 295.0 59.0 +Fc4 neg -.33 217.5 49.7 357.7 118.6 +Fc4 neg -.11 193.9 40.4 348.4 75.7 +Fc4 neg -.037 172.6 57.6 370.7 88.6 +Fc4 neg -.012 177.6 38.1 286.7 71.5 +Fc4 neg -.0041 275.4 67.9 253.3 45.0 +0170-3 33.3 8.8 57.2 3.2 +0170-1 41.3 8.5 47.0 10.5 +0170-.33 45.3 14.3 80.4 21.6 +00170-.11 42.2 12.4 103.8 32.8 +0170-.037 54.4 18.5 142.3 43.5 +0170-.012 86.2 24.4 203.8 55.6 +0170-.0041 186.7 21.0 249.3 92.5 +0170-.0014 231.2 56.0 286.1 112.8 +0170-.00046 246.4 22.7 254.2 70.5

This example illustrates that the anti TREM-1 Ab-0170 can effectively block TREM dependent cytokine production in macrophage cells derived from cynomolgus monkeys. The efficacy of this Ab supports its use in cynomolgus monkey in in vivo toxicology and disease treatment models.

Example 19: TNFalpha Release from Stimulated Peripheral Blood Mononuclear Cells can be Blocked by TREM-1 Antibodies

PBMC's, from a buffy coat and frozen in RPMI 1640 (Cat. no. 61870, Gibco, N.Y., USA), 20% FBS (Cat #16140-071, Gibco, N.Y., USA, 10% DMSO (Cat# D2650, Sigma, Steinheim, Germany), were thawed and washed twice in RPMI, 10% FBS, 1% Pen/Strep (Cat. no. 15070-06, Gibco, New York, USA), and resuspended in same medium to 4×10E6/ml. Cells were then distributed with 400.000 cells/well. 10 μg/ml PGN-SA (Cat # tlrl-pgnsa, Invivogen, San Diego, USA) and 0.2 μg/ml PGLYRP1 were added to the wells for stimulating the cells. Subsequently, the relevant isotype and TREM-1 antibodies were diluted in RPMI and added at 1.34 nM, and 0.167 nM respectively. TNFalpha release were measured by diaplex (Cat #880.090.001, Genprobe, Besancon, France) according to manufacturers protocol after 20 hrs incubation at 37° C., 5% CO₂. As shown in Table 13, below, the TREM-1 antibodies disclosed herein (mAbs 0044, 0070 and 0059) are all able to decrease the TNFalpha release from PBMC cells.

TABLE 15 Isotype at % Inhibition compared to isotype 1.34 nM 0 nM 0.167 nM a-Trem-1 0044 (mIgG2a) 100 100 68 a-Trem-1 0070 ((hIgG4) 100 117 76 a-Trem-1 0059 (hzIgG1.1) 100 105 61

The approximately 70% inhibition of TNFalpha release in PBMCs using a blocking TREM-1 antibody indicates a significant impact on cytokine levels in a stimulated cell culture.

Example 20: Anti-TREM-1 mAb Can Inhibit PGN+PGLYRP1-Induced TNFa Production in Normoxic Macrophages

Stimulation of macrophages using PGN-BS+human PGLYRP1 as a stimulant of the TREM-1 receptor can be blocked by anti-TREM-1 antibodies.

Monocytes were differentiated into M2 macrophages as in Example 15. All steps of the differentiation and stimulation of the cells were done in a 37° C., 5% CO2 incubator under normal atmospheric oxygen levels (normoxia). The differentiated M2 macrophages were resuspended in RPMI/10% FBS and plated out at 5×10E5 cells/ml in triplicate (unless otherwise noted) test wells. The cells were then stimulated for 24 hours with the following stimulations: no addition, PGLYRP1, PGN-BS (InVivogen, tlrl-pgnbs) (two sets of triplicates), PGN-BS+PGLYRP1 (three sets of triplicates), or PGN-BS+PGLYRP1 in the presence of anti-TREM1 or isotype control antibody. Supernatants were then harvested and analysed for TNFa using BioPlex (Bio-Rad, 171-B5026M). Antibodies (0.1 μg/ml) mAb-0122 and -0170 directed against TREM-1 were able to lower the TNF-alpha release.

TABLE 16 Donor 1 Donor 2 TNFa pg/ml TNFa pg/ml Macrophages stimulated with: Avg SD Avg SD No addition 0 0 0 0 PGLYRP1 0 0 0 0 PGN-BS 427 86 381 85 PGN-BS + PGLYRP1 728 293 771 220 PGN-BS + PGLYRP1 + hIgG4 987 183 884 41 isotype control PGN-BS + PGLYRP1 + mAb 0122 243 14 367 16 PGN-BS + PGLYRP1 + mAb 0170 122 106 224 54

This example illustrates that anti-TREM-1 mAb-0122 and -0170 can inhibit TNFa production from macrophages grown under normoxic conditions.

Example 21: TREM-1 Antibody Specifically Inhibits Rheumatoid Arthritis Synovial Fluid-Induced Response

The RA synovial fluid samples from patients suffering from rheumatoid arthritis were assayed for TREM-1 ligand activity in the BWZ reporter assay as described in Example 6. Briefly, synovial fluid was thawed, vortexed, and serially diluted, assayed in duplicate +/−10 μg/ml PGNECndi (Invivogen, San Diego, Calif., USA) with the addition of TREM-1 antibodies or a negative isotype control. The synovial fluid from a rheumatoid arthritis patient is able to trigger the BWZ/hTREM-1 reporter cell assay in a TREM-1 dependent manner which is further enhanced by adding MAB1278 (R&D Systems, Minneapolis, Minn. 55413, USA: Cat. no. MAB1278)) whereas the blocking TREM-1 antibodies disclosed herein are able to decrease this activation.

The antibodies were tested in two assays indicated by the two columns below, each antibody in concentrations ranging from 0.1 to 10 ug/ml. MAB1278 clearly enhanced the signal, whereas mAbs 0122 and 0170 decreased the signal compared to the isotype control.

TABLE 17 +IgG4 isotype Concentration +mAb 0122 +mAb 0170 +mAb 1278 control  10 ug/ml 80877 79731 52064 50304 1079000 1054000 306906 397556   1 ug/ml 74191 66458 48254 46978 1192000 1023000 398431 363267 0.1 ug/ml 133900 163521 246695 169483 828866 691379 293831 313445

Example 22: Cytokine Release from Synovial Tissue Cells from Rheumatoid Arthritis Patients Upon Stimulation with PGLYRP-1 can be Blocked by mAb 0170

Synovial tissue samples were obtained from RA patients during total knee replacement. Single suspension of synovial tissue cells was isolated by a digestion via 4 mg/ml of collagenase (cat#11088793001, Roche, Mannheim, Germany) and 0.1 mg/ml of DNase (cat#11284932001, Roche, Mannheim, Germany) for 1 h at 37 degrees C.

Synovial tissue cells at 1×10^5/well in culture medium RPMI (cat#R0883, St Louis, Mo., USA) +10% FCS (cat#50115, BioChrom AG, Grand Island, N.Y. 14072, USA) were stimulated with 4 ug/ml of PGLYRP1 and 1 ug/ml of PGN-ECNDi (cat# tlrl-kipgn, Invivogen, San Diego, Calif. 92121, USA) under hypoxic condition in the presence or absence of various concentrations of mAb 0170 or an isotype hIgG4 control. After 24 h incubation, cell supernatants were harvested, and cytokines were measured by either ELISA (TNFa (cat# DY210, R&D, Minneapolis, Minn. 55413 USA), IL-1b (88-7010-88, eBioscience, San Diego, Calif. 92121, USA), GM-CSF (cat#88-7339-88, eBioscience)) or Flowcytomix (TNFa, IL-1b, MIP-1b, MCP-1, IL-6, and IL-8 (cat#BMS, eBioscience). The cytokines were secreted from the synovial tissue cells upon stimulation with the TREM-1 ligand and specifically blocked by TREM-1 antibody mAb 0170.

Below is an example of such experiment, where either 4 ng/ml or 10 ng/ml mAb was used resulting in a decrease of cytokine release when treated with TREM-1 antibody mAb 0170.

TABLE 18 Cytokine PGN + PGN + PGLYRP1 + PGN + PGLYRP1 + (pg/ml) PGN PGLYRP1 10 ng/ml control 10 ng/ml mAb 0170 TNFalpha 624 1445 1034 429 MIP-1beta 2458 4395 3791 2321 MCP-1 273 471 391 210

TABLE 19 Cytokine PGN + PGN + PGLYRP1 + PGN + PGLYRP1 + (pg/ml) PGN PGLYRP1 4 ng/ml control 4 ng/ml 0170 IL-1beta 2419 3773 3477 2308 GM-CSF 182 616 656 431 IL-6 2057 4189 3475 1632 IL-8 2575 5509 4499 2112

This example shows that cells from synovial tissue from rheumatoid arthritis patients will respond to stimulation by the TREM-1 ligand, PGLYRP1, by secreting numerous cytokines which can be inhibited by mAb 0170.

Example 23: Type II PGLYRP1 Induced TNFalpha Release in Synovial Tissue Cells from Rheumatoid Arthritis Patients can be Blocked by TREM-1 Antibody mAb 0170

Synovial tissue samples were obtained from RA patients during total knee replacement. Single suspension of synovial tissue cells was isolated by a digestion via 4 mg/ml of collagenase (cat. no. 11088793001, Roche, Mannheim, Germany) and 0.1 mg/ml of DNase (cat. no. 11284932001, Roche, Mannheim, Germany) for 1 h at 37 degree. The synovial tissue cells (1×10^5/well in culture medium RPMI (cat. no. 22400105, Gibco, N.Y. 14072, USA) +10% FCS (cat. no. 50115, BioChrom AG, Berlin, Germany)) were co-cultured with various doses of HEK cells transiently transfected with type II PGLYRP1 under hypoxic condition in the presence or absence of 1 ug/ml of mAb 0170 or IgG4 isotype control. After 24 h incubation, cell supernatants were harvested, and cytokines were measured by TNFa ELISA (cat. no. DY210, R&D, Minneapolis, Minn. 55413 USA).

TABLE 20 Type II PGLYRP1 (HEK transfected)/ TNF-a (pg/ml) release Control HEK 1 × 10{circumflex over ( )}5 3 × 10{circumflex over ( )}4 1 × 10{circumflex over ( )}4 3 × 10{circumflex over ( )}3 1 × 10{circumflex over ( )}3 0 IgG4 + Type II cells 121.17 114.08 95.02 54.56 57.87 33.47 IgG4 + Control cells 55.65 63.73 57.99 33.78 36.40 36.32 mAb 0170 + Type II cells 44.05 44.67 44.40 39.45 44.29 31.40 mAb 0170 + Control cells 54.50 57.06 53.10 42.10 31.99 27.82

This example shows that the TREM-1 ligand (type II cells) induced TNF-alpha release in a dose-dependent manner in synovial tissue cells from rheumatoid arthritis patients compared to control cells (mock transfected). This TNFalpha response was blocked by mAb 0170 but not with isotype IgG4. The control cells were not affected.

Example 24: Platebound MAB1278 Induced IL-6 and TNFalpha Response in Macrophages, Showing Agonistic Features, Whereas mAbs 0122 and 0170 Did not

Stimulation of macrophages on platebound agonistic anti-TREM-1 antibodies induced production of IL-6 and TNFa. Monocytes were purified from healthy donor buffy coats using RosetteSep (StemCell Technologies, 15068) and differentiated into macrophages by culturing for 6 days in RPMI/10% FBS in the presence of 40 ng/ml human MCSF. The macrophages were then further differentiated to M2 macrophages by changing the media to growth media supplemented with 50 ng/ml human IL-4 and returning to the incubator for an additional 24 hours. On the seventh day, macrophages were recovered from the culture plates by washing with 1×PBS, followed by 5 mM EDTA in PBS. The plates were then returned to 37° C. for 30 minutes before the macrophages were washed off the plates. The macrophages were washed in RPMI/10% FBS before resuspending and plating out. The test wells had been pre-coated with the specified antibodies by incubating them overnight with antibody diluted in PBS, followed by washing ×3 in PBS. The resuspended macrophages were plated out at 5×10E5 cells/ml in triplicate test wells followed by incubation for 24 hours. (All steps of the differentiation and stimulation of the cells were done in a 37° C., 5% CO2 incubator under normal atmospheric oxygen levels (normoxia)). Supernatants were then harvested and analysed for IL-6 and TNFa using BioPlex (Bio-Rad, 171-B5006M and 171-B5026M).

Antibodies mAb-0122 and -0170 showed very low agonism whereas the MAB1278 antibody (RnD Systems, MAB1278) showed potent induction of both IL-6 and TNFa.

TABLE 21 IL-6 pg/ml TNFa pg/ml Platebound mAb stimulation: Avg SD Avg SD No antibody 1 3 0.3 0.8 mIgG1 isotype cntr 2 μg/ml 0 0 0 0 mIgG1 isotype cntr 6 μg/ml 0 0 0 0 mIgG1 isotype cntr 20 μg/ml 14 24 5 5 MAB1278 2 μg/ml 412 71 2004 451 MAB1278 6 μg/ml 877 38 6454 278 MAB1278 20 μg/ml 1352 76 7753 555 hIgG4 isotype cntr 2 μg/ml 5 5 2 1 hIgG4 isotype cntr 6 μg/ml 18 15 9 9 hIgG4 isotype cntr 20 μg/ml 37 3 34 1 mAb 0122 2 μg/ml 93 48 59 18 mAb 0122 6 μg/ml 126 8 105 17 mAb 0122 20 μg/ml 234 10 304 26 mAb 0170 2 μg/ml 137 29 76 21 mAb 0170 6 μg/ml 181 12 187 28 mAb 0170 20 μg/ml 277 15 629 108

This example illustrates that mAb-0122 and -0170 only show very low agonistic activity in macrophages and indicates true blocking features of these mAbs.

Example 25: Blocking TREM-1 in a Mouse Arthritis Model Reduces Disease

The experiments outlined in Table 22 were obtained in the DTH-arthritis model, which is a single paw arthritis model. Single paw arthritis was induced in female C57BL/6 mice by eliciting a classical delayed-type hypersensitivity (DTH) reaction in the right hind paw by immunisation and subsequent challenge with methylated bovine serum albumin (mBSA), with the modification that a cocktail of type II collagen monoclonal antibodies (anti-CII) was administered IV between the immunisation and challenge steps. The left hind paw received PBS challenge and functioned as an intra-animal control. Mice (10 mice/group) were treated 3 times/week with a TREM monoclonal antibody that specifically binds and blocks murine TREM-1, as determined using a murine version of the reporter assay described in Example 6. The first dose was administered on the day of immunization. Mice (9-10 mice/group) were treated with either a control antibody or PBS as a control. Paw swelling was measured from the day of arthritis induction and 11 days onwards. Results are presented as a mean area under the curve (AUC)±SEM. Statistical significance was tested by using a two sided unpaired t-test, 95% confidence interval.

TABLE 22 Effect of TREM-1 treatment on paw swelling (AUC-mm) in a mouse arthritis model. Effect Exper- measure iment TREM-1 mAb^(§) Control mAb^(§) PBS AUC-mm #1 8.03 +/− 1.01** 12.26 +/− 0.84 12.53 +/− 0.87 paw swelling AUC-mm #2 8.45 +/− 0.94** 11.71 +/− 0.22 12.89 +/− 0.36 paw swelling Means +/− SEM. ^(§)mice treated with 5 mg/kg, 3 times/week for 3 weeks **P ≤ 0.005, two sided unpaired t-test, 95% confidence interval vs. control mAb and vs. PBS

Example 26: Activated Neutrophils Release IL-8 which can be Blocked by TREM-1 mAbs

Neutrophils express TREM-1 and neutrophils also express the TREM-1 ligand. To test whether TREM-1 is involved in an autocrine stimulation loop in neutrophils, isolated neutrophils were stimulated with PGN-SA (InVivogen, tlrl-pgnsa), and the release of IL-8 into the culture medium was measured. TREM-1 antibodies mAb-0059, -0067, -0122, and -0170 were able to decrease the PGN-SA-induced IL-8 release. Neutrophils were isolated from human healthy donor whole blood and resuspended in RPMI/10% FBS at 1.5×10E6 cells/ml, and plated out into triplicate test wells pre-coated with Fibrinogen (pre-coated with 50 □1 of 1 mg/ml Fibrinogen (Sigma, F3879) in PBS for 2 hours at 37° C., followed by washing ×3 in PBS). The cells were tested under the following conditions: no added stimulation, 10 □g/ml PGN-SA only, or 10 □g/ml PGN-SA in the presence of mAb-0059, -0067, -0122, -0170 or isotype control antibody at 0.25 □g/ml. The samples were cultured 24 hours in a 37° C., 5% CO₂ incubator. Supernatants were then harvested and analysed for IL-8 using the Bio-plex Pro Human Cytokine IL-8 set (BioRad, 171-B5008M).

TABLE 23 Experiment 1 Experiment 2 Neutrophils IL-8, pg/ml Neutrophils IL-8, pg/ml stimulated with: Avg SD stimulated with: Avg SD No addition N.D. N.D. No addition 857 214 PGN-SA 562 54 PGN-SA 6116 191 PGN-SA + hIgG1.1 461 80 PGN-SA + hIgG4 6530 1962 isotype contr. isotype contr. PGN-SA + mAb 165 55 PGN-SA + mAb 2466 437 0059 0122 PGN-SA + mAb 183 77 PGN-SA + mAb 2171 480 0067 0170

This example illustrates that IL-8 release from neutrophils induced by stimulation with the bacterially derived PGN can be reduced by TREM-1 antibodies. Thus demonstrating that TREM-1 is involved in an autrocrine activation loop in neutrophils, and the TREM-1 antibodies are potentially useful in downregulating neutrophil responses.

Example 27: Activated Neutrophils can Stimulate Monocytes, which can be Blocked by Anti-TREM-1 mAbs

Activated neutrophils express the TREM-1 ligand. To test if activated neutrophils can stimulate other immune cells in a TREM-1-dependent manner, activated neutrophils were used to stimulate isolated monocytes and the release of TNFa into the culture medium was measured. TREM-1 antibodies mAb-0059 and -0170 were able to decrease the neutrophil-induced TNFa release from the monocytes.

Neutrophils were isolated from human healthy donor whole blood and resuspended in RPMI/10% FBS, and plated at 1.5×10E5 cells/well in poly-D-Lysine coated tissue culture 96-well plates (Corning, 3841). The neutrophils were then stimulated with 1 ng/ml PMA (Sigma, P1585)+20 □g/ml PGN-SA (InVivogen, tlrl-pgnsa) for 24 hours in a 37° C., 5% CO2 incubator. The cells were then washed gently ×3 with media before adding in freshly isolated monocytes. The monocytes were purified from healthy donor buffy coats using an EasySep kit (Stem cell technologies, 19059), and were plated out with 5×10E4 cells/well in the wells already containing activated, washed neutrophils. The following antibodies were added at 1 □g/ml: mAb-0059, mAb-0170, or hIgG4 isotype control. The cells were then cultured for another 24 hours before harvesting the supernatant. The supernatant was diluted 1:10 in RPMI/10% FNS before measuring TNFa by ELISA (eBioscience, BMS223INST).

TABLE 24 TNFa pg/ml Monocytes stimulated with: Avg SD No neutrophils 34 85 Activated neutrophils 299 67 Activated neutrophils + isotype control 232 32 Activated neutrophils + mAb 0059 72 14 Activated neutrophils + mAb 0170 129 9

This example illustrated that activated neutrophils can stimulate monocytes in a TREM-1-dependent manner to produce TNFa, and this can be blocked by mAb-0059 and mAb-0170 anti-TREM-1 antibodies. Anti-TREM-1 antibodies are therefore potentially useful for downregulating monocyte responses.

Example 28: Epitope Mapping by Protein Crystallography

Materials

The IgV-like domain of human TREM-1 (SEQ ID NO: 24) in a buffer consisting of 20 mM 2-(N-morpholino)ethanesulfonic acid, 150 mM NaCl, 5% (v/v) glycerol, pH 5.5 at a protein concentration of 11.7 mg/mL

The Fab region of mAb 0170 (SEQ ID NO: 25 and SEQ ID NO: 26) in a buffer consisting of 10 mM phosphate, 2.68 mM KCl, 140 mM NaCl, pH 7.4 at a protein concentration of 8.5 mg/mL.

Methods: Protein Complex Formation and Crystallization

The IgV-like domain of human TREM-1 was mixed with the Fab region of mAb 0170 in their original buffers in a 1:1 molar ratio, giving a final concentration of Fab of 7.1 mg/mL. The proteins were co-crystallized in a hanging drop vapour diffusion experiment by equilibration of droplets consisting of 2 μL protein solution mixed with 2 μL reservoir solution against a 0.5 mL reservoir composed of 0.01 M MgCl₂, 0.005 M NiCl₂, 0.1 M 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, 13(w/v) % polyethylene glycol 3350, pH 7.0. The crystals appeared as clusters of crystals, which were separated into single crystals and transferred to a drop consisting of 35(w/v) % polyethylene glycol 3350, 0.01 M MgCl₂, 0.005 M NiCl₂ and left to equilibrate in the drop for 15 seconds. The crystal was mounted in a 0.2 mm diameter litholoop (Molecular Dimensions Limited) and flash-cooled in liquid nitrogen.

X-Ray Diffraction Data Collection, Structure Determination and Refinement

Diffraction data were collected at a micromax-007HF Cu X-ray generator (Rigaku Europe) operated at 40 kV, 30 mAmp and equipped with Varimax HF optics (Cu K□, □=0.15418 nm) (Rigaku Europe), a Cryonix165 CCD (Rigaku Europe) and a Cryo-stream (Rigaku Europe) operated at 100 K. The raw data images were indexed, integrated and scaled using the XDS program package (Kabsch, Acta Crystallogr. D66, 133-144 (2010)). The space group of the crystal was P2(1), with unit cell parameters, a=62.3 Å, b=64.9 Å, c=74.4 Å, α=90°, β=75.2°, γ=90°. Data were collected to a resolution of 1.99 Å. The structure was solved by molecular replacement using the Phenix software (Adams et al., Acta Crystallogr. D66, 213-221 (2010)) as implemented in the CCP4i program suite (Potterton et al., Acta Crystallogr. D59, 1131-1137 (2003)). The search models were the structure of the mAb 0170 Fab fragment and the IgV-like domain from human TREM-1 (Kelker et al., J. Mol. Biol. 342, 1237-1248 (2004)). One copy of each molecule was located in the asymmetric unit. Structure refinement was carried out using Refmac5 (Murshudov er al., Acta Crystallogr. D53, 240-255 (1997)) from the CCP4i program suite. Coot version 7 (Emsley et al., Acta Crystallogr. D66, 486-501 (2010)) was used for manual structure rebuilding and validation.

Results and Discussion

The crystal structure of the complex between the Fab fragment of mAb 0170 and the IgV-like domain of human TREM-1 included E1-V219 (SEQ ID NO: 25), D1-C218 (SEQ ID NO: 26) and L24-T134 of SEQ ID NO: 24. The quality parameters of the structure were good with overall R-factor of the structure=21.1% and the Free R-factor=27.1%. The overall correlation coefficient was 0.93 and the diffraction-component precision index, DPI=0.2 Å (Cruickshank, Acta Crystallogr. D55, 583-601 (1999)). The root-mean-square deviation of the bond lengths in the structure from ideal bond lengths=0.0164 Å and the root-mean-square deviation from ideal bond angles=1.8661° (Engh and Huber, Acta Crystallogr. A47, 392-400 (1991)). Regions displaying intermolecular distances of less than or equal to 4 Å between the IgV-like domain of human TREM-1 and the Fab fragment of mAb 0170 were assigned to the epitope region of human TREM-1 (SEQ ID NO: 1). The analysis of intermolecular distances was carried out using the program NCONT in the CCP4 program suite (Potterton et al., Acta Crystallogr. D59, 1131-1137 (2003)). The analysis showed that human TREM-1 amino acid residues K40, D42, T44-K47 and Y90-L95, R97 defined the epitope.

While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now be apparent to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. 

The invention claimed is:
 1. An isolated antibody or fragment thereof, which competes with mAb 0170 for binding to a triggering receptor expressed on myeloid cells-1 (TREM-1) having an amino acid sequence set forth as SEQ ID NO: 1 (human TREM-1), SEQ ID NO: 12 or SEQ ID NO: 21 (cynomolgus monkey TREM-1), wherein the antibody or fragment thereof comprises a heavy chain variable region that comprises CDR1, CDR2, and CDR3 domains; and a light chain variable region that comprises CDR1, CDR2, and CDR3 domains, and wherein the heavy chain variable region CDR1 domain comprises amino acid residues 31 to 35 of SEQ ID NO: 4, the heavy chain variable region CDR2 domain comprises amino acid residues 50 to 68 of SEQ ID NO: 4, the heavy chain variable region CDR3 domain comprises amino acid residues 101 to 110 of SEQ ID NO: 4, the light chain variable region CDR1 domain comprises amino acid residues 24 to 38 of SEQ ID NO: 5, the light chain variable region CDR2 domain comprises amino acid residues 54 to 60 of SEQ ID NO: 5, and the light chain variable region CDR3 domain comprises amino acid residues 93 to 101 of SEQ ID NO:
 5. 2. The antibody or fragment thereof of claim 1, which specifically binds to D38 to F48 of SEQ ID NO:
 1. 3. The antibody or fragment thereof of claim 2, which further comprises a heavy chain constant region which is of a human IgG1, IgG2, IgG3, or IgG4 isotype.
 4. The antibody or fragment thereof of claim 2, which further comprises a heavy chain constant region which is of a human IgG1 isotype.
 5. A pharmaceutical composition comprising the antibody or fragment thereof of claim 4 and a pharmaceutically acceptable carrier.
 6. The antibody or fragment thereof of claim 2, which further comprises a heavy chain constant region which is of a human IgG4 isotype.
 7. A pharmaceutical composition comprising the antibody or fragment thereof of claim 6 and a pharmaceutically acceptable carrier.
 8. The antibody fragment of claim 2, which is a Fab, Fab′, F(ab′)₂, dAb, Fd, Fv, or a single chain Fv fragment.
 9. A pharmaceutical composition comprising the antibody or fragment thereof of claim 2 and a pharmaceutically acceptable carrier.
 10. The antibody or fragment thereof of claim 2, which binds human TREM-1 with a binding affinity (K_(D)) that is or 1×10⁻⁹M or less, as determined using surface plasmon resonance.
 11. A pharmaceutical composition comprising the antibody or fragment thereof of claim 10 and a pharmaceutically acceptable carrier.
 12. The antibody or fragment thereof of claim 1, which binds human TREM-1 with a binding affinity (K_(D)) that is or 1×10⁻⁹M or less, as determined using surface plasmon resonance.
 13. A pharmaceutical composition comprising the antibody or fragment thereof of claim 12 and a pharmaceutically acceptable carrier.
 14. A pharmaceutical composition comprising the antibody or fragment thereof of claim 1 and a pharmaceutically acceptable carrier. 